I'm really confused on this question, pls help

State the formula for density in words and mathematical symbols

Sex cells from female reproductive organ? 1) mitosis 2) fertilization 3) zygote 4) eggs 5) meiosis 6) sperm

6what is the importance of water on earth? a) it keeps the top layer of the geosphere cool b) it allows life to exist c) it provides ice at the poles d) it creates earth's blue color from space