What is the main idea of paragraph 3? “Bioassays usually do not identify which specific substances are toxic, or the amounts of toxic substances present. But they do provide a good indication of the total toxicity of samples, and they are a quick and inexpensive way to test for toxicity in many samples” A Bioassays are less expensive than other toxicity tests.
B Bioassays are used to indicate which toxic substances are present in a
sample.
C) Runoff water could be contaminated with toxic substances.
D) Bioassays are a convenient way to test whether substances may be toxic.