How much energy is available at the third trophic level if the first trophic level has 300,000
kilocalories of available energy and the loss rate between trophic levels is 90 percent?
A. 300.000 kilocalories
B. 30,000 kilocalories
C. 3000 kilocalories
. 300 kilocalories

What are two ways that harvesting algae from the ocean may benefit human society? how might the harvest of algae negatively impact the ocean communities where that algae grows? how could this be prevented?

Choose the incorrect statement (a) the motor end plate membrane is only capable of generating graded potentials, but it is contiguous with the skeletal muscle sarcolemma, which can generate action potentials. (b) propagation of an action potential through the t-tubules into the sarcoplasmic reticulum triggers the release of ca++ into the cytoplasm of a skeletal muscle fiber. (c) the generation of suprathreshold endplate potentials in multiple muscle fibers could be due to the increased frequency of action potential generation at the axon hillock of a single motor neuron. (d) a greater amount of ach would be found in the presynaptic vesicles of a motor unit that fired several action potentials after exposure to botulinum toxin, than in a motor unit that fired several action potentials after exposure to the venom of the krait snake (which contains α-bungarotoxin).

According to the article, what valid claim came from the national research council? there is no association between fluoride exposure and increased cancer risk in humans. there is a possible link between fluoride exposure and increased cancer risk in humans. there is a definite link between fluoride exposure and increased cancer risk in humans.