Considering how the body is organized, give one reason why it is so difficult for scientists to build a heart.

A)
The heart is a pump made of muscle and that is difficult to grow in the lab.

B)
Even if researchers build a heart, there is no guarantee that a person's body will accept it.

C)
Human hearts are not like any other animal hearts so there is not source for cells and tissues.
Eliminate

D)
The heart is made up of many different types of cells that are organized into different tissues.

How do antiviral drugs work? in your own words.

Which is an advantage of having memory cells when a pathogen is encountered for a second time. a) the memory cells are what proliferate into clones of cells in response to the binding of an antigen. b) memory cells are vital to the primary immune response in that they immediately recognize pathogens even at the first encounter. c) memory cells are essentially effector cells that are short lived and attack antigens even without having a receptor specific to that antigen. d) it ensures that more lymphocytes with a receptor specific to a particular antigen will be present than in a host that had never encountered that pathogen.

14. which of the following codons code for threonine? a. ucg b. ugu c. cga d. aca