Like humans, birds have fast twitch and slow twitch fibers. flying requires bursts of energy and rapid movement. what type of muscle fibers are most likely used when chickens fly?

fast twitch, because they produce small amounts of energy quickly

slow twitch, because they produce small amounts of energy quickly

slow twitch, because they can contract for long periods of time without fatiguing

fast twitch, because they produce excess atp

Fast twitch, because they produce small amounts of energy quickly

Explanation:

Fast twitch fibers can generate more force, but are quicker to fatigue when compared to slow-twitch fibers therefore, causing small burst of energy quickly

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).

cells use diffusion to get substances in and out of themselves. that diffusion will occur across the cell membrane or the outer covering of the cell. because we are talking about the surface of the cell, surface area and volume are  important factors here. as a cell increases in size, its surface area and volume increase as well.  we call that the surface area to volume ratio (sa: vol).  but the catch is that  volume increases at a greater rate than surface  area. in other words, as a cell gets bigger, the sa: vol gets smaller. so a really small cell like bacteria is mostly cell membrane (surface) with very little contents (volume). a really big cell like an egg, is mostly insides with a super thin membrane. so what ends up happening is that the cell cannot efficiently diffuse all of the stuff it needs in/out to survive. therefore cell size is limited to about 100mm. so how do we make organisms bigger than 100mm? cells divide! by dividing and becoming multicellular, organisms are able to grow!   check out the diagrams i attached to see the effect of sa: vol. i hope this ! good luck!