Q: What is required for a decay chain to end? Read this paragraph and choose the correct option from the provided answers: We have talked about the activity and decay of individual isotopes. In the real world, there is a decay chain that takes place until a stable end-product is produced. For U-238, the chain is a long one, with a mix of isotopes having very different half-lives. The end of the chain resides in lead, a stable element that does not decay further. Choices: - stable half-life - unstable end-product - radioactive cascade - stable end-product A:
stable end-product

Q: What term means that only molecules or ions of a certain size, shape, polarity or charge are capable of passing through the material? Read this paragraph and choose the correct option from the provided answers: Osmosis and Osmotic Pressure of Solutions A number of natural and synthetic materials exhibit selective permeation, meaning that only molecules or ions of a certain size, shape, polarity, charge, and so forth, are capable of passing through (permeating) the material. Biological cell membranes provide elegant examples of selective permeation in nature, while dialysis tubing used to remove metabolic wastes from blood is a more simplistic technological example. Regardless of how they may be fabricated, these materials are generally referred to as semipermeable membranes. Consider the apparatus illustrated in Figure 11.25, in which samples of pure solvent and a solution are separated by a membrane that only solvent molecules may permeate. Solvent molecules will diffuse across the membrane in both directions. Since the concentration of solvent is greater in the pure solvent than the solution, these molecules will diffuse from the solvent side of the membrane to the solution side at a faster rate than they will in the reverse direction. The result is a net transfer of solvent molecules from the pure solvent to the solution. Diffusion-driven transfer of solvent molecules through a semipermeable membrane is a process known as osmosis. Choices: - classic permeation - induced permeation - radiation permeation - selective permeation A:
selective permeation

Q: Q: What is the smallest contractile portion of a muscle? Read this paragraph and choose the correct option from the provided answers: 10.3 Muscle Fiber Contraction and Relaxation A sarcomere is the smallest contractile portion of a muscle. Myofibrils are composed of thick and thin filaments. Thick filaments are composed of the protein myosin; thin filaments are composed of the protein actin. Troponin and tropomyosin are regulatory proteins. Muscle contraction is described by the sliding filament model of contraction. ACh is the neurotransmitter that binds at the neuromuscular junction (NMJ) to trigger depolarization, and an action potential travels along the sarcolemma to trigger calcium release from SR. The actin sites are exposed after Ca++ enters the sarcoplasm from its SR storage to activate the troponin-tropomyosin complex so that the tropomyosin shifts away from the sites. The cross-bridging of myposin heads docking into actin-binding sites is followed by the "power stroke"the sliding of the thin filaments by thick filaments. The power strokes are powered by ATP. Ultimately, the sarcomeres, myofibrils, and muscle fibers shorten to produce movement. Choices: - filaments - cell - capillary - sarcomere A:
A: sarcomere

Question: Q: The water in some springs are hot because they're heated by what? Read this paragraph and choose the correct option from the provided answers: Some springs have water that contains minerals. Groundwater dissolves minerals out of the rock as it seeps through the pores. The water in some springs is hot because it is heated by hot magma. Many hot springs are also mineral springs. That's because hot water can dissolve more minerals than cold water. Choices: - gravity - the sun - fires - hot magma A:
Answer: hot magma

*Question*
Q: Who first proposed that earth is a magnet? Read this paragraph and choose the correct option from the provided answers: The molar mass of any substance is the mass in grams of one mole of representative particles of that substance. The representative particles can be atoms, molecules, or formula units of ionic compounds. This relationship is frequently used in the laboratory. Suppose that for a certain experiment you need 3.00 moles of calcium chloride (CaCl 2 ). Since calcium chloride is a solid, it would be convenient to use a balance to measure the mass that is needed. The molar mass of CaCl 2 is 110.98 g/mol. The conversion factor that can be used is then based on the equality that 1 mol = 110.98 g CaCl 2 . Dimensional analysis will allow you to calculate the mass of CaCl 2 that you should measure. Choices: - Albert Einstein - Isaac Newton - Marconi - william gilbert A:
**Answer**
william gilbert

(Q).
Q: What type of feeders are sea lilies and feather stars? Read this paragraph and choose the correct option from the provided answers: Explore the sea star's body plan (http://openstaxcollege. org/l/sea_star) up close, watch one move across the sea floor, and see it devour a mussel. Brittle stars belong to the class Ophiuroidea. Unlike sea stars, which have plump arms, brittle stars have long, thin arms that are sharply demarcated from the central disk. Brittle stars move by lashing out their arms or wrapping them around objects and pulling themselves forward. Sea urchins and sand dollars are examples of Echinoidea. These echinoderms do not have arms, but are hemispherical or flattened with five rows of tube feet that help them in slow movement; tube feet are extruded through pores of a continuous internal shell called a test. Sea lilies and feather stars are examples of Crinoidea. Both of these species are suspension feeders. Sea cucumbers of class Holothuroidea are extended in the oral-aboral axis and have five rows of tube feet. These are the only echinoderms that demonstrate "functional" bilateral symmetry as adults, because the uniquely extended oral-aboral axis compels the animal to lie horizontally rather than stand vertically. Choices: - deposit feeder - bottom feeder - silt feeders - suspension feeders A:
(A).
suspension feeders