Answer: Because they have built up immunity from past medications.
Explanation: As people get sick and are given antibiotics the 99.9 % are removed but that one percent from the bacteria is able to overcome the antibiotics and make itself stronger and immune to the medicines, then the bacteria evolves and a new person will get infected and will need stronger antibiotics further more the cycle is repeated.
Yes the population would crash
Answer:
neurotransmitter is a chemical messenger that carries, boosts, and balances signals between neurons (also known as nerve cells) and target cells throughout the body.
The rough endoplasmic reticulum (versus the smooth), which is where the ribosomes are and make proteins.
Yes it is true because after many years of water or wind eroding away at the rock will cause it to break up into tiny pieces
