Stone tools we’re first used around 3,300 BCE
If a p53 gene is defective it may cause cell cycle to stop functioning normally. Without this cell cycle check, cells will divide continuosly creating many chromosomal damage.
The troposphere has the highest density.
Answer:
1. Essential organs form during early development
Explanation:
Harmful chemicals (toxins) cause the most disease when they are present during fetal development, because organ systems are being developed and the rate of growth is very fast.
