Natural selection acts on variation by:
a. allowing the bad genes to quickly spread through the population
c. allowing the bad genes to slowly spread through the population
b. allowing the good genes to slowly spread through the population
d. allowing the good genes to quickly spread through the population

Natural selection is the differences in survival and reproduction as the consequence of differences in genotypes and, consequently, phenotypes.  It is one of the factors of evolution that affects a frequency of different variations. In natural selection, genotype variations that will increase the chance of survival and reproduction of some organism are preserved and will be inherited Thus, "good genes" will be inherited. But, as the evolution, it will be slow process, since rarely evolution happens quickly.

metamorphism is the change of minerals or geologic texture (distinct arrangement of minerals) in pre-existing rocks (protoliths), without the protolith melting into liquid magma (a solid-state change). the change occurs primarily due to heat, pressure, and the introduction of chemically active fluids. i hoped i !

answer:

convection currents in the magma drive plate tectonics. heat generated from the radioactive decay of elements deep in the interior of the earth creates magma (molten rock) in the aesthenosphere. the aesthenosphere (70 ~ 250 km) is part of the mantle, the middle sphere of the earth that extends to 2900 km.