Answer:
The activity of cyclic AMP phosphodiesterase is prevented by caffeine. The caffeine prevents further dissociation of cAMP, which eventually increases the response within the body. The activity of neurotransmitters, that is, of noradrenaline or epinephrine, gets increased due to enhancement in response.
This further enhances the activity of the heart, the rate of muscle contractions, blood pressure that further helps in delivering more oxygen to the brain, and other parts of the body. Thus, the inhibition of the enzyme cyclic AMP phosphodiesterase helps the athletes to prevent the wall.
Answer:
Density is nearly 3 cabs per hectare
Explanation:
Given -
There are three three intertidal regions.
Area of each intertidal region is 
hectares.
Number of crab in the intertidal regions are as follows -
Intertidal region I - 7
Intertidal region I - 2
Intertidal region I - 6
Sum of crabs in all three regions is equal to
Total area of all three intertidal regions is equal to
hectares
Now density per hectare is equal to total population of crab divided by total area of all the three intertidal regions
Density 
Density is nearly 3 cabs per hectare
Answer;
A) Blood pressure decreases greatly; blood flow to the heart is inadequate, and blood pressure decreases.
Explanation;
-With negative feedback, the output reduces the original effect of the stimulus. While in a positive feedback system, the output enhances the original stimulus.
-Negative feedback is the most commonly used feedback loop in the body. Negative feedback is used to negate or counteract a stimulus without completely eradicating it.
-One key difference between the two feedback is that positive feedback loops are used to eradicate a stimulus. Another key difference is that responses through positive feedback become more amplified over time. So once a stimulus activates a positive feedback loop it is not turned off until the stimulus is completely removed.
Answer: when one is lost, one is formed
Well, the asthenosphere is located in the upper mantle. So that is how they are related.
