I need help rounding to the nearest hundredth

Which prefix mean under less or below

Which of the following is the earliest era of earth's geologic time scale? cenozoic mesozoic precambrian paleozoic

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