How do the two main parts nervous system work together to of the perceive and react to an animal's environment?​

answer; i believe that the correct answer is(d) nondisjunction during meiosis;

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).

they have identical fossils of organisms that have evolved over time.

both have animal fossils preserved in them due to weathering and erosion.

they contain different fossils because life on earth has changed through time.

the fossils in them were formed on the surface of earth due to exposure to sunlight.

for a different answer set the answer would be because the oxygen in the water had depleted (apex)