(3)

Dark phase is also known as light independent phase, unlike light phase, it does not require light as an essential factor, thus can take place both in the presence and absence of light.

(1)

Stomata is a tiny pore in leaves that help in gaseous exchange, so if the stomata gets blocked due to oil, gaseous exchange will be affected and hence rate of photosynthesis gets lowered. Thus, both assertion and reason are correct and reason is the correct explanation of the assertion.

(2)

Presence of HCl in stomach is necessary for digestion because acidic medium activates the action of gastric juice. HCl maintains a strong acidic pH, of about 1–2 in the stomach. HCl helps to activate Pepsinogen to pepsin which digests proteins to peptones and proteases. HCl inhibits the growth of germs and also kills them those may have entered the stomach along with the food. So, thus it can be said that HCl kills bacteria but that does not help in digestion. Thus, both assertion and reason are correct but reason is not the correct explanation of the assertion.

(3)

Pancreatic amylase is a starch splitting enzyme like salivary amylase, so it cannot digest proteins. Thus, assertion is true but reason is false.

(2)

In most animals, tissue oxidation is carried out by aerobic respiration. But sometimes in aerobically respiring organisms, anaerobic metabolism takes place in certain tissues like skeletal muscles which do not get as much as required oxygen and produce lactic acid.

(4)

Left ventricle has thickest muscles because it pumps the blood to the whole body. Thus, assertion is false but reason is true.

(1)

Warm-blooded animals need high energy to maintain their body temperature and thus their left and right side of the heart are separated for more efficient supply of oxygen to the body. Thus, both assertion and reason are correct and reason is the correct explanation of the assertion.

(1)

During the day transpiration becomes the main driving force for pulling up water. But at night since there is no sunlight transpiration does not take place, so water is pulled up due to root pressure. Thus, both assertion and reason are correct and reason is the correct explanation of the assertion.

(2)

Sphygmomanometer is the instrument used to measure blood pressure. Whatever be the value it will be obtained after measuring with this. This has no relation with the normal adult blood pressure. Thus, both assertion and reason are correct but reason is not the correct explanation of the assertion.

(2)

Ureter’s function is to carry urine from kidney to the bladder, it does not depend on what lining it has. Thus, both assertion and reason are correct but reason is not the correct explanation of the assertion.