Why is biodiversity important in a marine ecosystem

Modern sea star larvae resemble some primitive vertebrate larvae. this similarity may suggest that primitive vertebrates

Which one is an advantage of external fertilization a. the offspring are genetically identical to the parents b. more eggs can be fertilzed at one time c. more sperm can be released at one time d. more protection is available for developing plz

As the earth formed, the force of gravity increased due to increased mass. what effect did this increased gravity have on the forming planet?