During Mendel's first set of experiments, he allowed true-breeding tall plants to cross with true-breeding short plants. What happened when he allowed the
F, offspring from this first set of experiments to self-pollinate?

substitution is the answer in this case

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