Some heterotrophs, such as paramecia, engulf algae and consume the food produced by the algae. the algae benefits by using the carbon dioxide produced by the paramecia. what is this relationship an example of?
a. mutualism
b. parasitism
c. neutralism
d. commensalism

What adaptation is apparent in the bodies of the three tortoise species shown in figure 16-2

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.

What was the purpose of mendel's experiments with dihybrid crosses? a. to determine if dna was a transforming factor b. to determine if traits could be recessive c. to determine if traits affected each other d. to determine if traits had more than one allele