Earth's history. In the worst one, 250 million years ago, 96 percent of marine species and 70 percent of land species died off. It took millions of years to recover.
1. to repair damaged cells
Answer:
1. sperm cell
2.testicles
3.egg
4.ovary
5.fertilization
6.fertilized egg = foetus
Explanation:
alpha cells are glucagon and beta cells are insulin
Smog is an abiotic factor affecting a biotic factor(s).
This is because smog isn't a living organism so it is abiotic while humans are multicellular organisms so therefore, they are biotic factors.
Smog has a negative effect on many biotic factors.