Railroad, barbed wire and the modern water pump
Answer:
There was plenty of good land available for farming.
Answer:
The primary and secondary responses are equal
Explanation:
Primary and secondary are considered to be two responses of immune to the antigen.
Primary response occurs at the first encounter between the antigen and immune. This response can be as long as 14 days depending on the antigen category.
There are two cells in the body that act as a defensive system and antibodies against antibodies.
the secondary response occurs when a person exposed to the same antigen repeatedly
