Tavi was running at a fast pace in a marathon. which of the following describes how the tavi's nervous system worked with his circulatory system to him to maintain homeostasis? a) the brain sends signals to the veins to decrease the blood pressure to the legs so that muscles have less mass b) the brain send signals to the blood vessels in the legs to dilate so that there is increased blood flow c) the heart send signals to the brain which then releases a hormone that causes the blood flow to decrease to the stomach d) the brain informed the heart to decrease its rate of pumping in order to slow the flow of blood during exercise

The correct answer is B) The brain send signals to the blood vessels in the legs to dilate so that there is increased blood flow.

During running Tavi's muscles need oxygen to break down fats and carbohydrates for energy. As we know that blood work as carrier for oxygen so to make room for fresh oxygen, the brain send signals to the blood vessels to dilate to increase the flow of blood in legs. The process of dilation of vessels in our body is called vasodilation.

ans.

dna fingerprinting is defined as a process that determines the dna characteristics of an individual. these dna characteristics are unique among individuals as their fingerprints, so it is known as dna fingerprinting.

steps of dna fingerprinting includes extraction of dna from sample, amplification of dna, restriction digestion of amplified dna, and then analysis of dna by gel electrophoresis, respectively.

thus, the next step performed by the scientist is 'to cut the amplified dna (obtained by polymerase chain reaction) by restriction enzymes that cleave the dna into fragments and their analysis.'

it provides an alternative energy pathway for the reaction to proceed.

a catalyst is a substance that speeds up the rate of a chemical reaction but is not consumed during the course of the reaction.

catalysts increase the rate of reaction without being used up. they do this by lowering the activation energy needed. with a catalyst, more collisions result in a reaction, so the rate of reaction increases. different reactions need different catalysts.

a catalyst works by providing an alternative reaction pathway to the reaction product. the rate of the reaction is increased as this alternative route has a lower activation energy than the reaction route not mediated by the catalyst.