rajpurkar/squad huggingface dataset:
Title: LaserDisc

There were also 12 cm (4.7 in) (CD size) "single"-style discs produced that were playable on LaserDisc players. These were referred to as CD Video (CD-V) discs, and Video Single Discs (VSD). A CD-V carried up to five minutes of analog LaserDisc-type video content (usually a music video), as well as up to 20 minutes of digital audio CD tracks. The original 1989 release of David Bowie's retrospective Sound + Vision CD box set prominently featured a CD-V video of Ashes to Ashes, and standalone promo CD-Vs featured the video, plus three audio tracks: "John, I'm Only Dancing", "Changes", and "The Supermen".

Question: In contrast to large LD disks, what is the size of a standard CD?
Answer: 12 cm (4.7 in)

Question: What were CD size "single"-style discs called that were compatible with LaserDisc players?
Answer: CD Video (CD-V) discs, and Video Single Discs (VSD)

Question: How much video content could be stored on a CD-V disk?
Answer: up to five minutes of analog LaserDisc-type video content

Question: What were CD-V's video capacities usually used for?
Answer: music video

Question: Which artist released a music video and three audio tracks on CD-V in 1989?
Answer: David Bowie
Title: LaserDisc

CD-Vs are not to be confused with Video CDs (which are all-digital and can only be played on VCD players, DVD players, CD-i players, computers, and later-model LaserDisc players, such as the DVL series from Pioneer that can also play DVDs). CD-Vs can only be played back on LaserDisc players with CD-V capability. VSDs were the same as CD-Vs, but without the audio CD tracks. CD-Vs were somewhat popular for a brief time worldwide, but soon faded from view. VSDs were popular only in Japan and other parts of Asia, and were never fully introduced to the rest of the world.

Question: What were VSDs lacking that CD-Vs included?
Answer: audio CD tracks

Question: In what areas of the world were VSDs popular?
Answer: only in Japan and other parts of Asia

Question: Were VSDs or CD-Vs all digital and also playable on DVD players?
Answer: VSDs
Title: Annelid

The annelids are bilaterally symmetrical, triploblastic, coelomate, invertebrate organisms. They also have parapodia for locomotion. Most textbooks still use the traditional division into polychaetes (almost all marine), oligochaetes (which include earthworms) and leech-like species. Cladistic research since 1997 has radically changed this scheme, viewing leeches as a sub-group of oligochaetes and oligochaetes as a sub-group of polychaetes. In addition, the Pogonophora, Echiura and Sipuncula, previously regarded as separate phyla, are now regarded as sub-groups of polychaetes. Annelids are considered members of the Lophotrochozoa, a "super-phylum" of protostomes that also includes molluscs, brachiopods, flatworms and nemerteans.

Question: What kind of symmetry do annelids have?
Answer: bilateral

Question: What do annelids use to move?
Answer: parapodia

Question: Which subtype of annelids includes most marine worms?
Answer: polychaetes

Question: Which subtype of annelids includes earthworms?
Answer: oligochaetes

Question: Since 1997, what are leeches seen as a subgroup of?
Answer: oligochaetes
Title: Annelid

The basic annelid form consists of multiple segments. Each segment has the same sets of organs and, in most polychaetes, has a pair of parapodia that many species use for locomotion. Septa separate the segments of many species, but are poorly defined or absent in others, and Echiura and Sipuncula show no obvious signs of segmentation. In species with well-developed septa, the blood circulates entirely within blood vessels, and the vessels in segments near the front ends of these species are often built up with muscles that act as hearts. The septa of such species also enable them to change the shapes of individual segments, which facilitates movement by peristalsis ("ripples" that pass along the body) or by undulations that improve the effectiveness of the parapodia. In species with incomplete septa or none, the blood circulates through the main body cavity without any kind of pump, and there is a wide range of locomotory techniques – some burrowing species turn their pharynges inside out to drag themselves through the sediment.

Question: What separates many annelids' segments?
Answer: Septa

Question: Which annelids show no segmentation?
Answer: Echiura and Sipuncula

Question: What end of annelids with well-developed segmentation has muscles that act like hearts?
Answer: front

Question: What is movement by ripples called?
Answer: peristalsis

Question: What movement method do some burrowing annelids use?
Answer: turn their pharynges inside out to drag themselves
Title: Annelid

Although many species can reproduce asexually and use similar mechanisms to regenerate after severe injuries, sexual reproduction is the normal method in species whose reproduction has been studied. The minority of living polychaetes whose reproduction and lifecycles are known produce trochophore larvae, that live as plankton and then sink and metamorphose into miniature adults. Oligochaetes are full hermaphrodites and produce a ring-like cocoon around their bodies, in which the eggs and hatchlings are nourished until they are ready to emerge.

Question: How do annelids normally reproduce?
Answer: sexual reproduction

Question: What can asexual reproduction techniques help annelids do?
Answer: regenerate after severe injuries

Question: What larvae live like plankton?
Answer: trochophore

Question: What annelids are hermaphrodites?
Answer: Oligochaetes

Question: What annelids make a cocoon in a ring around themselves?
Answer: Oligochaetes
Title: Annelid

Earthworms are Oligochaetes that support terrestrial food chains both as prey and in some regions are important in aeration and enriching of soil. The burrowing of marine polychaetes, which may constitute up to a third of all species in near-shore environments, encourages the development of ecosystems by enabling water and oxygen to penetrate the sea floor. In addition to improving soil fertility, annelids serve humans as food and as bait. Scientists observe annelids to monitor the quality of marine and fresh water. Although blood-letting is no longer in favor with doctors, some leech species are regarded as endangered species because they have been over-harvested for this purpose in the last few centuries. Ragworms' jaws are now being studied by engineers as they offer an exceptional combination of lightness and strength.

Question: How do earthworms help the soil they live in?
Answer: aeration and enriching

Question: How much of near-shore marine annelids are burrowing?
Answer: up to a third

Question: How do burrowing marine annelids help ocean ecosystems?
Answer: enabling water and oxygen to penetrate the sea floor

Question: What annelids' jaws are being studied by engineers?
Answer: Ragworms

Question: Why are some leeches endangered?
Answer: they have been over-harvested
Title: Annelid

Since annelids are soft-bodied, their fossils are rare – mostly jaws and the mineralized tubes that some of the species secreted. Although some late Ediacaran fossils may represent annelids, the oldest known fossil that is identified with confidence comes from about 518 million years ago in the early Cambrian period. Fossils of most modern mobile polychaete groups appeared by the end of the Carboniferous, about 299 million years ago. Palaeontologists disagree about whether some body fossils from the mid Ordovician, about 472 to 461 million years ago, are the remains of oligochaetes, and the earliest indisputable fossils of the group appear in the Tertiary period, which began 65 million years ago.

Question: Why are annelid fossils rare?
Answer: annelids are soft-bodied

Question: What fossil signs of annelids are found?
Answer: jaws and the mineralized tubes that some of the species secreted

Question: How old is the earliest annelid fossil?
Answer: 518 million years ago

Question: What types of annelids appeared 299 million years ago?
Answer: modern mobile polychaete groups

Question: What period started around 472 million years ago?
Answer: the mid Ordovician
Title: Annelid

No single feature distinguishes Annelids from other invertebrate phyla, but they have a distinctive combination of features. Their bodies are long, with segments that are divided externally by shallow ring-like constrictions called annuli and internally by septa ("partitions") at the same points, although in some species the septa are incomplete and in a few cases missing. Most of the segments contain the same sets of organs, although sharing a common gut, circulatory system and nervous system makes them inter-dependent. Their bodies are covered by a cuticle (outer covering) that does not contain cells but is secreted by cells in the skin underneath, is made of tough but flexible collagen and does not molt – on the other hand arthropods' cuticles are made of the more rigid α-chitin, and molt until the arthropods reach their full size. Most annelids have closed circulatory systems, where the blood makes its entire circuit via blood vessels.

Question: What externally divides annelids' segments?
Answer: shallow ring-like constrictions called annuli

Question: What divides annelids' segments internally?
Answer: septa ("partitions")

Question: What do the segments of an annelid share?
Answer: a common gut, circulatory system and nervous system

Question: What covers an annelid's exterior?
Answer: a cuticle

Question: What is an annelid's cuticle made of?
Answer: collagen
Title: Annelid

Most of an annelid's body consists of segments that are practically identical, having the same sets of internal organs and external chaetae (Greek χαιτη, meaning "hair") and, in some species, appendages. However, the frontmost and rearmost sections are not regarded as true segments as they do not contain the standard sets of organs and do not develop in the same way as the true segments. The frontmost section, called the prostomium (Greek προ- meaning "in front of" and στομα meaning "mouth") contains the brain and sense organs, while the rearmost, called the pygidium (Greek πυγιδιον, meaning "little tail") or periproct contains the anus, generally on the underside. The first section behind the prostomium, called the peristomium (Greek περι- meaning "around" and στομα meaning "mouth"), is regarded by some zoologists as not a true segment, but in some polychaetes the peristomium has chetae and appendages like those of other segments.

Question: What language does the term 'chaetae' come from?
Answer: Greek

Question: What does 'chaetae' mean?
Answer: hair

Question: Which parts of annelids are different from true segments?
Answer: the frontmost and rearmost sections

Question: What language does 'prostomium' come from?
Answer: Greek

Question: What does 'pygidium' mean?
Answer: little tail
Title: Annelid

Annelids' cuticles are made of collagen fibers, usually in layers that spiral in alternating directions so that the fibers cross each other. These are secreted by the one-cell deep epidermis (outermost skin layer). A few marine annelids that live in tubes lack cuticles, but their tubes have a similar structure, and mucus-secreting glands in the epidermis protect their skins. Under the epidermis is the dermis, which is made of connective tissue, in other words a combination of cells and non-cellular materials such as collagen. Below this are two layers of muscles, which develop from the lining of the coelom (body cavity): circular muscles make a segment longer and slimmer when they contract, while under them are longitudinal muscles, usually four distinct strips, whose contractions make the segment shorter and fatter. Some annelids also have oblique internal muscles that connect the underside of the body to each side.

Question: How are the layers arranged in annelids' cuticles?
Answer: spiral in alternating directions

Question: What are annelids' cuticles made out of?
Answer: collagen fibers

Question: What do non-cuticle annelids use to protect their skin?
Answer: mucus-secreting glands in the epidermis

Question: What layer is under the epidermis?
Answer: the dermis

Question: What does 'coelom' mean?
Answer: (body cavity
Title: Annelid

The setae ("hairs") of annelids project out from the epidermis to provide traction and other capabilities. The simplest are unjointed and form paired bundles near the top and bottom of each side of each segment. The parapodia ("limbs") of annelids that have them often bear more complex chetae at their tips – for example jointed, comb-like or hooked. Chetae are made of moderately flexible β-chitin and are formed by follicles, each of which has a chetoblast ("hair-forming") cell at the bottom and muscles that can extend or retract the cheta. The chetoblasts produce chetae by forming microvilli, fine hair-like extensions that increase the area available for secreting the cheta. When the cheta is complete, the microvilli withdraw into the chetoblast, leaving parallel tunnels that run almost the full length of the cheta. Hence annelids' chetae are structurally different from the setae ("bristles") of arthropods, which are made of the more rigid α-chitin, have a single internal cavity, and are mounted on flexible joints in shallow pits in the cuticle.

Question: What are parapodia?
Answer: limbs

Question: What do chetoblast cells do?
Answer: hair-forming

Question: What hair-like extensions do chetoblasts make?
Answer: microvilli

Question: What are setae?
Answer: bristles
Title: Annelid

Nearly all polychaetes have parapodia that function as limbs, while other major annelid groups lack them. Parapodia are unjointed paired extensions of the body wall, and their muscles are derived from the circular muscles of the body. They are often supported internally by one or more large, thick chetae. The parapodia of burrowing and tube-dwelling polychaetes are often just ridges whose tips bear hooked chetae. In active crawlers and swimmers the parapodia are often divided into large upper and lower paddles on a very short trunk, and the paddles are generally fringed with chetae and sometimes with cirri (fused bundles of cilia) and gills.

Question: What are cirri?
Answer: fused bundles of cilia

Question: What kind of parapodia do burrowing annelids often have?
Answer: ridges whose tips bear hooked chetae

Question: What type of annelids have limb-like parapodia?
Answer: polychaetes

Question: What are parapodia?
Answer: unjointed paired extensions of the body wall
Title: Annelid

The brain generally forms a ring round the pharynx (throat), consisting of a pair of ganglia (local control centers) above and in front of the pharynx, linked by nerve cords either side of the pharynx to another pair of ganglia just below and behind it. The brains of polychaetes are generally in the prostomium, while those of clitellates are in the peristomium or sometimes the first segment behind the peristomium. In some very mobile and active polychaetes the brain is enlarged and more complex, with visible hindbrain, midbrain and forebrain sections. The rest of the central nervous system is generally "ladder-like", consisting of a pair of nerve cords that run through the bottom part of the body and have in each segment paired ganglia linked by a transverse connection. From each segmental ganglion a branching system of local nerves runs into the body wall and then encircles the body. However, in most polychaetes the two main nerve cords are fused, and in the tube-dwelling genus Owenia the single nerve chord has no ganglia and is located in the epidermis.

Question: What are ganglia?
Answer: local control centers

Question: What is an annelid's brain in a ring around?
Answer: the pharynx

Question: What is a pharynx?
Answer: throat

Question: Where are clitellates' brains?
Answer: in the peristomium or sometimes the first segment behind the peristomium

Question: Where are polychaetes' brains?
Answer: in the prostomium
Title: Annelid

As in arthropods, each muscle fiber (cell) is controlled by more than one neuron, and the speed and power of the fiber's contractions depends on the combined effects of all its neurons. Vertebrates have a different system, in which one neuron controls a group of muscle fibers. Most annelids' longitudinal nerve trunks include giant axons (the output signal lines of nerve cells). Their large diameter decreases their resistance, which allows them to transmit signals exceptionally fast. This enables these worms to withdraw rapidly from danger by shortening their bodies. Experiments have shown that cutting the giant axons prevents this escape response but does not affect normal movement.

Question: What species group are annelids' muscle control similar to?
Answer: arthropods

Question: What are giant axons?
Answer: the output signal lines of nerve cells

Question: How do annelids withdraw from danger?
Answer: shortening their bodies
Title: Annelid

The sensors are primarily single cells that detect light, chemicals, pressure waves and contact, and are present on the head, appendages (if any) and other parts of the body. Nuchal ("on the neck") organs are paired, ciliated structures found only in polychaetes, and are thought to be chemosensors. Some polychaetes also have various combinations of ocelli ("little eyes") that detect the direction from which light is coming and camera eyes or compound eyes that can probably form images. The compound eyes probably evolved independently of arthropods' eyes. Some tube-worms use ocelli widely spread over their bodies to detect the shadows of fish, so that they can quickly withdraw into their tubes. Some burrowing and tube-dwelling polychaetes have statocysts (tilt and balance sensors) that tell them which way is down. A few polychaete genera have on the undersides of their heads palps that are used both in feeding and as "feelers", and some of these also have antennae that are structurally similar but probably are used mainly as "feelers".

Question: What kind of things can annelids' sensors detect?
Answer: light, chemicals, pressure waves and contact

Question: What does 'nuchal' mean?
Answer: on the neck

Question: What type of annelids have nuchal organs?
Answer: polychaetes

Question: What are the nuchal organs thought to do?
Answer: chemosensors

Question: What term means 'little eyes'?
Answer: ocelli
Title: Annelid

Most annelids have a pair of coelomata (body cavities) in each segment, separated from other segments by septa and from each other by vertical mesenteries. Each septum forms a sandwich with connective tissue in the middle and mesothelium (membrane that serves as a lining) from the preceding and following segments on either side. Each mesentery is similar except that the mesothelium is the lining of each of the pair of coelomata, and the blood vessels and, in polychaetes, the main nerve cords are embedded in it. The mesothelium is made of modified epitheliomuscular cells; in other words, their bodies form part of the epithelium but their bases extend to form muscle fibers in the body wall. The mesothelium may also form radial and circular muscles on the septa, and circular muscles around the blood vessels and gut. Parts of the mesothelium, especially on the outside of the gut, may also form chloragogen cells that perform similar functions to the livers of vertebrates: producing and storing glycogen and fat; producing the oxygen-carrier hemoglobin; breaking down proteins; and turning nitrogenous waste products into ammonia and urea to be excreted.

Question: What are coelomata?
Answer: body cavities

Question: What are annelids' body cavities separated from other segments by?
Answer: septa

Question: What are annelids' body cavities separated from each other by?
Answer: vertical mesenteries

Question: What is the mesothelium made of?
Answer: modified epitheliomuscular cells
Title: Annelid

Many annelids move by peristalsis (waves of contraction and expansion that sweep along the body), or flex the body while using parapodia to crawl or swim. In these animals the septa enable the circular and longitudinal muscles to change the shape of individual segments, by making each segment a separate fluid-filled "balloon". However, the septa are often incomplete in annelids that are semi-sessile or that do not move by peristalsis or by movements of parapodia – for example some move by whipping movements of the body, some small marine species move by means of cilia (fine muscle-powered hairs) and some burrowers turn their pharynges (throats) inside out to penetrate the sea-floor and drag themselves into it.

Question: How does peristalsis work?
Answer: waves of contraction and expansion that sweep along the body

Question: Why are annelids' segments like water-balloons?
Answer: the septa enable the circular and longitudinal muscles to change the shape of individual segments

Question: What are phrynges?
Answer: throats

Question: What are cilia?
Answer: fine muscle-powered hairs
Title: Annelid

The fluid in the coelomata contains coelomocyte cells that defend the animals against parasites and infections. In some species coelomocytes may also contain a respiratory pigment – red hemoglobin in some species, green chlorocruorin in others (dissolved in the plasma) – and provide oxygen transport within their segments. Respiratory pigment is also dissolved in the blood plasma. Species with well-developed septa generally also have blood vessels running all long their bodies above and below the gut, the upper one carrying blood forwards while the lower one carries it backwards. Networks of capillaries in the body wall and around the gut transfer blood between the main blood vessels and to parts of the segment that need oxygen and nutrients. Both of the major vessels, especially the upper one, can pump blood by contracting. In some annelids the forward end of the upper blood vessel is enlarged with muscles to form a heart, while in the forward ends of many earthworms some of the vessels that connect the upper and lower main vessels function as hearts. Species with poorly developed or no septa generally have no blood vessels and rely on the circulation within the coelom for delivering nutrients and oxygen.

Question: What can coelomocyte cells defend against?
Answer: parasites and infections

Question: What type of pigment is dissolved in annelids' blood?
Answer: Respiratory

Question: What runs the length of annelids' bodies with well-developed septa?
Answer: blood vessels

Question: What do annelids without septa have to use for circulation?
Answer: circulation within the coelom
Title: Annelid

However, leeches and their closest relatives have a body structure that is very uniform within the group but significantly different from that of other annelids, including other members of the Clitellata. In leeches there are no septa, the connective tissue layer of the body wall is so thick that it occupies much of the body, and the two coelomata are widely separated and run the length of the body. They function as the main blood vessels, although they are side-by-side rather than upper and lower. However, they are lined with mesothelium, like the coelomata and unlike the blood vessels of other annelids. Leeches generally use suckers at their front and rear ends to move like inchworms. The anus is on the upper surface of the pygidium.

Question: What type of annelids are very different from others?
Answer: leeches and their closest relatives

Question: What type of tissue takes up most of the body of a leech?
Answer: connective tissue layer of the body wall

Question: How many coelomata do leeches have?
Answer: two

Question: What lines the coelomata of leeches?
Answer: mesothelium

Question: What do leeches use to move?
Answer: suckers at their front and rear ends