The answer is natural selection.
In natural selection, genotype variations that will increase the chance
of survival and reproduction of some organism are preserved and will be
inherited. Red and green colors of butterflies increased the chance of their <span>survival and reproduction, so these traits will pass to the next generation.</span>
<span>The hyphae, or feeding structures, reach deep into the wood to obtain nutrients.</span>
The answer is D. The natural selection is a theory which illustrates the gradual process of evolution in the population due to the change of environment. The key point is the mutation (variation) exists in the population before the environment changing. For C, if the environment does not change, though the adaptation is useful to environment, it will not be selected. Because the organisms without the adaptation will not die.
I’m not sure but I think the answer is B or D
Thyriod gland is the right answer
