Answer:
The behavior of chromosomes during meiosis and fertilization is responsible for most of the variation that arises in each generation. Three mechanisms contribute to genetic variation arising from sexual reproduction: independent assortment of chromosomes, crossing over, and random fertilization.
Answer: because they are situated near aquifers
Explanation:
Aquifers is a underground layer of rock which can hold and release water in desirable amounts so petroleum industries claims the well are safe.
Answer:
A
Explanation:
Tilling agitates the topsoil and removes ‘unnecessary’ vegetation so the main crop can grow without competition. Tilling improves soil aeration and drainage for plants to grow well. Nonetheless, it can lead to other consequences such as soil erosion because it loosens the soil and makes it easy to be carried away by wind and water.
Option D – amphibians may use their skin for gas exchange is the characteristic feature of amphibians that differs from reptiles.
Explanation:
The amphibian skin is moist, thin and marbled and supplied by blood vessels running on its surface. The moisture present in the skin dissolves the oxygen present in its surrounding which is absorbed by the blood vessels. Special glands help the amphibians to keep the skin moist.
The very thick and tough scales present on the reptiles prevent them to absorb oxygen through their skin. Hence, they breathe and respire through their lungs.
Amphibians have three-chambered heart. They do not develop amniotic eggs. Adult amphibians although spend much time on land, they breed only in water due to the absence of amniotic sac
.
Answer:
The correct answer is option c, that is, lactic acid.
Explanation:
One can determine the anaerobic function of muscles by observing the levels of lactic acid buildup in muscles. The production of lactic acid in muscles takes place by the process of anaerobic respiration. At the time of rigorous training or exercise, one requires more amount of energy for a short burst of time.
As oxygen is already used for higher purposes in the body, the levels of oxygen get reduced for performing any more activities. Thus, in order to generate more energy the process of anaerobic respiration takes place. Anaerobic respiration is the form of respiration that takes place in the absence of oxygen. In the process, one molecule of glucose gets transformed into two molecules of lactic acid, which gets accumulated in the muscles. This production of lactic acid provides a quick form of energy, which is utilized at the time of intense training and thus, one can check the anaerobic functioning of the muscles by observing the levels of lactic acid in the muscles.
