The classic phenotypic ration of 9: 3: 3: 1 is the basis of which of mendel's principles?
a. segregation
b. independent assortment

Independent assortment.

Explanation:

Mendel is known as the father of genetics. He has explained the law of purity of gametes, law of segregation, law of independent assortment and the concept of dominance.

The law of independent assortment explains that in the pair of the contrasting traits, the segregation of one pair of traits is independent on the other pair of trait. This law had been generated by the dihybrid cross. The ratio of the dihybrid cross that follows the independent assortment is 9:3:3:1.

Thus, the correct answer is option (B).

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