Task: Question Answering
Input (English): Context: Algae (singular "alga" ) is an informal term for a large, diverse group of photosynthetic organisms which are not necessarily closely related, and is thus polyphyletic. Included organisms range from unicellular genera, such as "Chlorella" and the diatoms, to multicellular forms, such as the giant kelp, a large brown alga which may grow up to 50 m in length. Most are aquatic and autotrophic and lack many of the distinct cell and tissue types, such as stomata, xylem, and phloem, which are found in land plants. The largest and most complex marine algae are called seaweeds, while the most complex freshwater forms are the Charophyta, a division of green algae which includes, for example, "Spirogyra" and the stoneworts., The heterokonts or stramenopiles (formally, Heterokonta or Stramenopiles) are a major line of eukaryotes currently containing more than 25,000 known species. Most are algae, ranging from the giant multicellular kelp to the unicellular diatoms, which are a primary component of plankton. Other notable members of the Stramenopiles include the (generally) parasitic oomycetes, including "Phytophthora" of Irish potato famine infamy and "Pythium" which causes seed rot and damping off., Zooplankton are heterotrophic (sometimes detritivorous) plankton. Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word "zooplankton" is derived from the Greek "zoon", meaning "animal", and "", meaning "wanderer" or "drifter". Individual zooplankton are usually microscopic, but some (such as jellyfish) are larger and visible with the naked eye., Diatoms are a major group of algae, and are among the most common types of phytoplankton. Diatoms are unicellular, although they can form colonies in the shape of filaments or ribbons (e.g. "Fragilaria"), fans (e.g. "Meridion"), zigzags (e.g. "Tabellaria"), or stars (e.g. "Asterionella"). The first diatom formally described in scientific literature, the colonial "Bacillaria paradoxa", was found in 1783 by Danish naturalist Otto Friedrich Müller. Diatoms are producers within the food chain. A unique feature of diatom cells is that they are enclosed within a cell wall made of silica (hydrated silicon dioxide) called a frustule. These frustules show a wide diversity in form, but are usually almost bilaterally symmetrical, hence the group name. The symmetry is not perfect since one of the valves is slightly larger than the other, allowing one valve to fit inside the edge of the other. Fossil evidence suggests that they originated during, or before, the early Jurassic period. Only male gametes of centric diatoms are capable of movement by means of flagella. Diatom communities are a popular tool for monitoring environmental conditions, past and present, and are commonly used in studies of water quality., The Coscinodiscophyceae are a class of diatom. They are similar to the Centrales, a traditional, paraphyletic subdivision of the heterokont algae known as diatoms. The order is named for the shape of the cell walls (or valves or frustules) of centric diatoms, which are circular or ellipsoid in valve view. The valves often bear radially symmetrical ornamental patterns that can appear as dots when viewed with an optical microscope. Some also bear spines on their valves, which may either increase cell surface area and reduce sinking, or act as a deterrent to zooplankton grazers. Unlike pennate diatoms, centric diatoms never have a raphe., Tabellaria is a genus of diatoms (Bacillariophyceae). They are cuboid in shape, and the frustules (siliceous cell walls) are attached at the corners so that the colonies assume a zigzag shape., Coscinodiscophycidae or Coscinodiscineae is a grouping of Coscinodiscophyceae , previously known as `` Centrales '' , a paraphyletic order of centric diatoms , a major group of algae and one of the most common members of the phytoplankton ., Subject: coscinodiscophycidae, Relation: parent_taxon, Options: (A) animal (B) bacillaria (C) bacillariophyceae (D) bear (E) centrales (F) chlorella (G) coscinodiscophyceae (H) diatom (I) oomycetes (J) paradoxa (K) phytophthora (L) pythium
Output (English): bacillariophyceae