Which of the following would be considered a source of error in an experiment

a) only three house flies were collected for an experiment

b) a beaker is knocked over and the contents are spilled on the floor

c) the data do not support the hypothesis

d) an incorrect average is calculated for the control group

parasites can detrimentally affect their host, but also must not allow their host to die before they can complete their life cycle. some parasites have complex life cycles with many different hosts, and have had to find ways of persisting in many different environments during the change from one host to another. ectoparasites live outside the body of the host, and can more easily  disperse, but are  more exposed to predators, parasites, parasitoids. endoparasites live inside the body of the host, and are therefore protected from the outside environment. but they can be  attacked by the host's immune system. they have therefore developed  mechanisms for dispersal such as  complex life cycles.

"do a testcross with a homozygous recessive plant."