I believe it would be mesentery
Answer:
C. factories
Explanation:
Factories release several gases and waste thata re toxic to the environment and considered pollutants.
Answer:
The steel plow and barbed wire
Explanation:
It was in 1837 when John Deere, a blacksmith from Illinois invented a steel mouldboard plough that was strong enough to cut through the stubborn roots of the prairie grasses. This invention turned millions of acres of prairie land into fields for arable crops and grazing ground for huge herds of domesticated cattle. The starving Indians who were displaced resorted to slaughtering the bison in 1872 to 1874 that resulted in the decrease of its population from 7.5M animals to about 750 only.
Answer:
after a vaccine is injected the body creates an immune response that produces memory cells so next time a pathogen invades the body is prepared