Sickle cell disease provides an example for which principle of molecular genetics? A. A point mutation always causes a significant change in phenotype. B. A point mutation always causes a change to an amino acid sequence, which may affect phenotype. C. A significant change in phenotype may cause a genetic mutation. D. A change to one amino acid in a protein may cause a significant change in phenotype.

D. A change to one amino acid in a protein may cause a significant change in phenotype.

if you know your abc's you should be able to get your answer or just use google

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