Answer:
B. Directional selection
Explanation:
When natural selection starts to choose one phenotypes that is an extreme (as in, a really small neck or a really long neck), this is an example of <u>directional selection.</u> It makes sense for giraffes to have evolved this way, because the longer the neck, the more ably they can eat food from high branches. The more food they could get, the more chance of reproduction, the more "evolutionarily fit" they are.
Stabilizing selection is when national selection picks average phenotypes (like a medium-sized neck). Disruptive selection is when the extremes are both picked (like all the medium-sized neck giraffes die, and two different species start to emerge). Sexual selection is picking a mate based on traits. Clearly, those answers don't work here.
Nearly all life on Earth ultimately gets its energy from the sun, which gets "its"energy through nuclear fusion. <span>With the exception of hydrogen, all of the chemical elements needed for life were produced by nuclear fusion of lighter elements, either in the cores of stars or in the shock waves of supernova explosions.</span>
The mechanical and chemical receptors that control digestive activity are located in the walls of the tract organs.
