After allowing his F1 crosses to self-pollinate, Mendel observed that

Explanation:

First-generation (F1) progeny only showed the dominant traits, but recessive traits reappeared in the self-pollinated second-generation (F2) plants in a 3:1 ratio of dominant to recessive traits. Mendel then crossed these pure-breeding lines of plants and recorded the traits of the hybrid progeny

the correct answer is sex-linked recessive.

i just took the test

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