Answer the following question given this paragraph: H2 + O2 H2O This is an example of a chemical equation, which is a concise way of representing a chemical reaction. The initial substances are called reactants, and the final substances are called products. Unfortunately, it is also an incomplete chemical equation. The law of conservation of matter says that matter cannot be created or destroyed. In chemical equations, the number of atoms of each element in the reactants must be the same as the number of atoms of each element in the products. If we count the number of hydrogen atoms in the reactants and products, we find two hydrogen atoms. But if we count the number of oxygen atoms in the reactants and products, we find that there are two oxygen atoms in the reactants but only one oxygen atom in the products. What can we do? Can we change the subscripts in the formula for water so that it has two oxygen atoms in it? No; you cannot change the formulas of individual substances because the chemical formula for a given substance is characteristic of that substance. What you can do, however, is to change the number of molecules that react or are produced. We do this one element at a time, going from one side of the reaction to the other, changing the number of molecules of a substance until all elements have the same number of atoms on each side. To accommodate the two oxygen atoms as reactants, let us assume that we have two water molecules as products:. Q: Initial substances are called reactants, and the final substances are called what? Choices: - exports - imports - reactors - products A:
products
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Answer the following question given this paragraph: 6. Mercury is small, rocky and covered with craters. Why?. Q: Mercury is small, rocky and covered with what objects? Choices: - rivers - volcanoes - diamonds - craters A:
craters
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Answer the following question given this paragraph: The autonomic nervous system serves as the relay between the CNS and the internal organs. It controls the lungs, the heart, smooth muscle, and exocrine and endocrine glands. The autonomic nervous system controls these organs largely without conscious control; it can continuously monitor the conditions of these different systems and implement changes as needed. Signaling to the target tissue usually involves two synapses: a preganglionic neuron (originating in the CNS) synapses to a neuron in a ganglion that, in turn, synapses on the target organ (Figure 16.24). There are two divisions of the autonomic nervous system that often have opposing effects: the sympathetic nervous system and the parasympathetic nervous system. The sympathetic nervous system is responsible for the immediate responses an animal makes when it encounters a dangerous situation. One way to remember this is to think of the "fight-or-flight" response a person feels when encountering a snake ("snake" and "sympathetic" both begin with "s"). Examples of functions controlled by the sympathetic nervous system include an accelerated heart rate and inhibited digestion. These functions help prepare an organism's body for the physical strain required to escape a potentially dangerous situation or to fend off a predator. Q: The autonomic nervous system serves as the relay between what and the internal organs? Choices: - hormones - somatic system - peripheral nervous system - central nervous system A:
central nervous system
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Answer the following question given this paragraph: Q: In animals, what process occurs only in germ cells, which are in the ovaries or testes? Choices: - mitosis - electrolysis - reproduction - meiosis A:
meiosis
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