Amother sprints across the yard to grab her small child before he enters the street. the mother is using her a. type i a slow-twitch muscle fibers that provided her with a fast burst of movement b. type ii b fast-twitch muscle fibers that respond quickly and provide her with speed and strength c. type i b intermediate-twitch muscle fibers that respond quickly because they are delivered energy aerobically d. type ii a fast-twitch muscle fibers that act rapidly because they are delivered energy anaerobically

The answer is "B. type II B fast-twitch muscle fibers that respond quickly and provide her with speed and strength".

Fast-twitch muscles separate into two classes: moderate fast-twitch (type IIa) and fast-twitch (type IIb or IIx). Moderate fast-twitch muscles are thicker, faster to contract, and destroy more quickly than slow-twitch. Fast-twitch, the most ground-breaking and least in continuance, are initiated when the body nears greatest effort.  

Here's the means by which it works: During aerobic activities, for example, running or swimming, slow-twitch fibers are the first to contract. At the point when the slow-twitch fibers wind up drained, fast-twitch fibers start to assume control.  

fluid balance is an aspect of the homeostasis of organisms in which the amount of water in the organism needs to be controlled, via osmoregulation and behavior, such that the concentrations of electrolytes (salts in solution) in the various body fluids are kept within healthy ranges. the core principle of fluid balance is that the amount of water lost from the body must equal the amount of water taken in.