Answer: Directional selection occurs when individuals with traits on one side of the mean in their population survive better or reproduce more than those on the other. ... Directional selection does the “heavy lifting” of evolution by tending to move the trait mean toward the optimum for the environment.
<span>gametes would be the correct answer.</span>
According to the second law of thermodynamics, energy is never 100% efficient because some of the energy disperses as heat.
<span>vaccine
The wording given is pretty much the exact definition of a vaccine. The key to how a vaccine works is that it provides to the immune system, samples of the surface proteins of the infectious materials. With those samples available, the immune system is able to produce antibodies that react to those proteins.</span>