Viruses cause diseases by destroying

They destroy cells that are normal. Then they use those cells to multiply and produce other viruses like themselves.

Explanation:

hormones in blood stream

image: dtc.ucsf.edu

endocrine glands secrete hormones into the blood stream near them; the hormones then travel in our bloodstream until it reaches its destination, called a target cell, in distance parts of the body. in the target tissue, hormones lock onto the target’s plasma membrane, called the receptor site.

any abiotic or biotic factor in an ecosystem that causes a population's size to slow or decrease is a limiting factor.