Ectotherms are more common in some ecosystems than in others. Where are ectotherms the LEAST common, and for what reason?

a.

a very cold ecosystem, because they would lose too much body heat

b.

an aquatic ecosystem, because they would lose too much heat to the water

c.

a hot, rainy ecosystem, because they depend on dry surfaces to maintain body temperature

d.

a hot, dry ecosystem, because they would overheat without a steady supply of water

a.  a very cold ecosystem, because they would lose too much body heat

Explanation:

Ectotherms would be least common in very cold ecosystem, because they would lose too much body heat.

Generally, ectotherms are organisms whose internal physiological temperature requirement depends on external sources. They generate very little heat internally and as such, rely on heat sources in the environment for the necessary physiological heat for their bodies.

Consequently, ectotherms live in environments where temperature are more or less constant or constantly seek out external sources of heat for their bodies.

In a very cold environment, the opportunity to seek out external source of heat would not be possible for ectotherms, and body heat would be lost to the environment in the process of maintaining constant body temperature. Hence, they are least likely to occupy this kind of environment.

The correct option is a.

after receiving a stimus, the sensory receptors send(s) signals to the appropriate area of the body.  

the must be sensory neurons.  

hope its .

the dna molecules have a negative charge because of the phosphate groups in their sugar-phosphate backbone, so they start moving through the matrix of the gel towards the positive pole. power is turned on and dna fragments migrate through gel (towards the positive electrode).

explanation: