How is it that DDT and PCB pollution continue today even though these pollutants have been banned in the U.S. for many years?
What will be an ideal response?
PCBs and DDT are synthetic organic compounds that are unusually persistent in the environment. As a result, quantities of these pollutants that were used many years ago are still present in the soil and can still find their way into the sea where they can pollute. In addition, DDT and PCBs that made it into the sea are highly concentrated in the sediment where they leach out into the water column very slowly.
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Which of the following types of plant hormones appears to regulate the expression of genes associated
with a plant's growth responses to light?
a. salicylic acid b. brassinosteroids c. gibberellins d. jasmonates e. oligosaccharins
All fungi are __________ that secrete digestive enzymes on organic matter and absorb released nutrients. Fill in the blank(s) with the appropriate word(s)
The initial reaction of the Krebs cycle involves the addition of a
What will be an ideal response?
The type of receptor that consists only of a naked nerve fiber ending is called a
A. Pacinian corpuscle. B. Meissner's corpuscle. C. nociceptor. D. cochlear hair cell. E. cone.