Ais a section of a chromosome that codes for a trait. the specific combination of alleles an organism has is called its which affect(s) the organism'

A gene is a section of a chromosome that codes for  trait.The specific combination of alleles an organism has is called its genotype which affects the organisms features.

Explanation:

      n

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