A Researcher Has Isolated a Protein Produced by a Snail

Multiple Choice

A researcher has isolated a protein produced by a snail and thought to be an intercellular chemical signaling agent.The researcher will incubate this agent with snail cells to test whether a specific cellular response occurs.What control should be run at the same time?

A) Incubate normal snail cells with a solution that does not contain the signal protein.
B) Incubate normal snail cells with a solution containing signal protein that has been chemically altered.
C) Incubate normal snail cells with a solution that contains a signal protein other than the one being investigated.
D) Incubate mutant snail cells known to be incapable of the cellular response with the signal protein.
E) Incubate mutant snail cells that constantly carry out the cellular response with the signal protein.