The water would freeze across the surface of the lake, blocking the dissolving of oxygen and nutrients. <span>Water is actually less dense when frozen, which is why ice cubes and ice bergs all float. This is also why you can ice skate on a lake if the ice gets thick enough on the surface. Many organisms that live in freezing lakes have special adaptations which help them survive.</span>
Rabbit ear size tends to decrease as latitude increases. this is an example of a cline
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A cline can be described as a change of the biological trait of a species across its geographical range. A cline can be genetic for example, change in the allele frequency, or phenotypic (change in body size). The change can be shown as continuous gradation, or it can be more abrupt from one geographic region to the next.
Answer:
c. Pyridostigmine binds to the acetylcholinesterase active site and prevents sarin from binding to and modifying the enzyme active site.
Explanation:
Sarin is a toxic compound which inhibits acetylcholinesterase enzyme. This enzyme degrades the neurotransmitter acetylcholine after the required muscle cell stimulation. In absence of its activity, acetylcholine is not degraded and the muscle cells are stimulated uncontrollably. The muscles are not able to relax which ultimately proves fatal for the victim.
Pyridostigmine is also an acetylcholinesterase inhibitor like Sarin. However its period of inhibition is short compared to organophosphorus inhibitors like sarin. It competes with sarin and replaces it in the active site of acetylcholinesterase. The enzyme is still inhibited but for a shorter time as compared to inhibition by Sarin. Hence after sometime, it becomes functional again and resumes its normal activity. Acetycholine starts getting degraded relaxing the muscles.
I would say "gene", as it is the basic unit of heredity.<span />
