One of the factor is the Sun's elevation where the UV reaches us at a much lower frequency when the sun is more distant. Next is our ozone, with our ozone depleting as time goes by, the amount of solar energy it can diffuse is much lesser thus the heat is much more than the previous decades.
Answer:
a. Directional selection favors one end of the phenotype distribution, whereas
stabilizing selection favors intermediate over extreme phenotypes
Explanation:
Directional selection is called directional because it favors one phenotype over another, and stabilizing selection finds a balance between phenotypes.
It is relative dating because no scientist can tell the actually time that the layers of rocks where formed or when the fossil began to degrade