(Q).
Answer the following question given this paragraph: The overall balanced equation for a chemical reaction does not always tell us how a reaction actually proceeds. In many cases, the overall reaction takes place in a series of small steps. An elementary step (or elementary reaction) is one step in a series of simple reactions that show the progress of a reaction at the molecular level. In terms of collision theory, each elementary step corresponds to a single collision. A reaction mechanism is the sequence of elementary steps that together comprise an entire chemical reaction. As an analogy, consider the route that you might take while driving to the grocery store. That route may consist of several turns, similar to the elementary steps. The overall reaction specifies only the beginning point (your house) and the final destination (the store), with no information about the specifics in between. Q: What is the sequence of elementary steps that together comprise an entire chemical reaction called? Choices: - reaction circle - mechanical mechanism - basic reaction - reaction mechanism A:
(A).
reaction mechanism

(Q).
Answer the following question given this paragraph: Macrophages are large WBCs that can also swallow and destroy old and dying cells, bacteria, or viruses. Below, a macrophage is attacking and swallowing two particles, possibly disease-causing pathogens ( Figure below ). Macrophages also release chemical messages that cause the number of WBCs to increase. Q: Macrophages, which can swallow and destroy old and dying cells, bacteria, or viruses, are large types of what cells? Choices: - red blood cells - white brain cells - dendritic cells - white blood cells A:
(A).
white blood cells

(Q).
Answer the following question given this paragraph: hollow, sac-like organ that stores urine until it is excreted from the body. Q: What is the hollow sac like organ that stores urine until it is excreted? Choices: - kidney - ureter - tumor - bladder A:
(A).
bladder