Acetylcholine is a neurotransmitter that binds to receptors on skeletal muscle cells. the receptor-signal complex brings about a series of events that result in contraction of skeletal muscle. venom from black widow spiders causes an explosive release of acetylcholine. what would that do to its victims?

paralysis, lack of breath and death (because of a great deal of Acetylcholine)

Explanation:

The receptor-signal complex brings about a series of events that result in contraction of skeletal muscle. So, if a black widow spider bites you, its venom will cause your muscular system to paralyze, as well as your lack of  breathing and lack of heartbeat leading you to die.

two jet streams that directly affect the formation of weather in the continental part are a polar jet and a subtropical jet. they are responsible for the transportation of weather systems, which directly affect people. the polar front is the boundary between cold air from the north pole and warmer equatorial air. both the polar jet and the subtropical jet blow from the west to the east, and follow the boundary between cold and warm air.

the strongest jet streams are polar jets, while subtropical jets are somewhat weaker.

the right answer is c. the polar jet stream is generaly stronger than the subtropical jet stream.

even though you have attached neither the chart nor the generalizations, i have located them online. the right answer is d, since they are asking you about a generalization. you can only infer from the chart that between 2008 and 2009 the number of employed workers decreased significantly (from over 115 millions to 107 millions approximately), which signals some type of economic crisis.