The concentration of toxic chemicals as it progresses through the food web. a. increases b. decreases c. remains the same d. cannot be predicted

The appropriate answer is a. Toxic chemicals increases as it progresses through the food Web. As organisms lower in the food chain feed on matter that has been tainted by toxins, organisms higher on the chain or their predators also feed on them. The toxins are therefore concentrated as one moves up the food chain. Mercury is one toxin that moves up the food chain in this way. Mercury concentrations are high in fish.

There are four nitrogenous bases that make up dna. the two pyramidines are thymine and cytosine. the two purines are adenine and guanine. these bases pair in a very specific way. adenine - thymineguanine - cytosine i remember it like this: a tall, good cat.