The characteristic of life that relies on the sun is the need for energy. Every living thing needs energy in order to survive, and almost every form of life on Earth depends on the sun for this energy. The sun's energy is captured and harnessed by the process of photosynthesis.
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.
They developed to be protected by the hard shell from parasites and ther predators.
The purpose of the Open Door Policy was to collaborate with other nations to maintain a common price level for free trade in China. The Open Door policy started in 1899. The correct answer is B.
