Cold and extremely down climate is experienced in these locations, this is due to the lack of exposure to the sun's rays. The North and South Pole of the earth are also responsible for many meteorological and astronomical occurrences that protects earth and its inhabitants from the harsh exposure to the sun's rays.
D. More economically developed countries
Answer:
D. By diffusion across a capillary wall
Explanation:
D is the best answer because gas exchange takes place in our lungs. Our lungs have alveoli which have a network of tiny blood vessels called capillaries, here the O2 diffuses the capillary wall to enter the bloodstream, and similarly CO2 diffuses out and we exhale it our from our lungs.
The correct answer is: A. A change in a cell's genetic material.
Mutations occur in DNA as a result of mistakes during the DNA replication (when repair mechanisms don’t fix it) or as the result of environmental factors (e.g. UV light). Mutations can have positive impact, by increasing the genetic variation or can have negative effect, causing the diseases or cancer.
