Which events contributed to life evolving on Earth? Check all that apply

Me with biology endocrine system crossword also image left i need with hw

The greenhouse effect a. something that has occurred for millions of years b. an unnatural phenomenon caused by humans that maintains earths temperature range. c. the results of the differences in the angle of the suns rays d. an unnatural phenomenon that causes heat energy to be radiated back into the atmosphere

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