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C. elegans Experimental Control Group

APBIO-E3EXPY

C. elegans, a nematode or "round worm," is a model organism in biology. A group of AP biology students was investigating associative learning in C. elegans. C. elegans feeds on bacteria, a particular strain of E. coli OPI150.

For one week, when students added E. coli OPI150 to the nematode culture, they also added salt ($NaCl$). Then, students placed the nematodes on a Petri dish with two choices, one mL of $NaCl$ solution and one mL of water, as seen in the image below.

Identify an appropriate control group in this experiment.

Created for Albert.io by Jennie Edgar. Copyright 2016.

A

An appropriate control would be to put the nematodes on a Petri dish without any drops of liquid to determine if the worms are attracted to one side of the choice chamber or not.

B

An appropriate control would be to put the nematodes on a Petri dish with salt water to see the effect of salt water on the behavior of C. elegans.

C

An appropriate control would be to put the nematodes on a Petri dish with just plain water on both sides to determine if liquid was an attractant to the worms.

D

An appropriate control group is to add the same amount of liquid to both sides of the Petri dish to maintain a constant level of liquid in the experiment.