What genotype does a heterozygous individual have if the uppercase alphabet a denotes dominant gene and lowercase alphabet a denotes a recessive gene?
a. aa
b. aa
c. aa
d. aaa

the earth is thought to have been formed about 4.6 billion years ago by collisions from a cloud of hydrogen, helium, rock, ice and other materials. these were pulled together by gravity to form objects in and around earth like- asteroids and small early planets called planetesimals.

so, the best possible answer to this question will be option d- to harden materials to form different parts of earth’s layers