Xerophthalmia is a medical condition in which the eye fails to produce tears. It may be caused by a deficiency in vitamin A and is sometimes used to describe that lack, although there may be other causes. Xerophthalmia caused by a severe vitamin A deficiency is described by pathologic dryness of the conjunctiva and cornea. The conjunctiva becomes dry, thick and wrinkled. If untreated, it can lead to corneal ulceration and ultimately to blindness as a result of corneal damage.

Correct Option: A

Xerophthalmia is a medical condition in which the eye fails to produce tears. It may be caused by a deficiency in vitamin A and is sometimes used to describe that lack, although there may be other causes. Xerophthalmia caused by a severe vitamin A deficiency is described by pathologic dryness of the conjunctiva and cornea. The conjunctiva becomes dry, thick and wrinkled. If untreated, it can lead to corneal ulceration and ultimately to blindness as a result of corneal damage.

A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions. Human cells have 23 pairs of chromosomes (22 pairs of autosomes and one pair of sex chromosomes), giving a total of 46 per cell.

Correct Option: D

A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions. Human cells have 23 pairs of chromosomes (22 pairs of autosomes and one pair of sex chromosomes), giving a total of 46 per cell.

Vitamin B₁₂ also called cobalamin, is a watersoluble vitamin with a key role in the normal functioning of the brain and nervous system, and for the formation of blood. Vitamin B₁₂ is found in foods that come from animals, including fish and shellfish, meat (especially liver), poultry, eggs, milk, and milk products. While lacto-ovo vegetarians usually get enough B₁₂ through consuming dairy products, vegans will lack B₁₂ unless they consume B₁₂-containing dietary supplements or B₁₂-fortified foods.

Correct Option: B

Vitamin B₁₂ also called cobalamin, is a watersoluble vitamin with a key role in the normal functioning of the brain and nervous system, and for the formation of blood. Vitamin B₁₂ is found in foods that come from animals, including fish and shellfish, meat (especially liver), poultry, eggs, milk, and milk products. While lacto-ovo vegetarians usually get enough B₁₂ through consuming dairy products, vegans will lack B₁₂ unless they consume B₁₂-containing dietary supplements or B₁₂-fortified foods.

Roundworms, or nematodes, are a group of invertebrates (animals having no backbone) with long, round bodies. Most parasitic roundworm eggs or larvae (immature form) are found in the soil and enter the human body when a person picks them up on the hands and then transfers them to the mouth. The eggs or larvae also can enter the human body directly through the skin. With the exception of the parasitic roundworm that causes trichinosis, mature adult roundworms eventually end up or live in human large intestines and cause infection and disease.

Correct Option: D

Roundworms, or nematodes, are a group of invertebrates (animals having no backbone) with long, round bodies. Most parasitic roundworm eggs or larvae (immature form) are found in the soil and enter the human body when a person picks them up on the hands and then transfers them to the mouth. The eggs or larvae also can enter the human body directly through the skin. With the exception of the parasitic roundworm that causes trichinosis, mature adult roundworms eventually end up or live in human large intestines and cause infection and disease.

Insulin storage vesicles in humans and many other species contain high concentrations of Zn₂+ and Ca₂+ ions. Zinc plays an important role in insulin hexamerisation, which is closely related to some of the processes in insulin biosynthesis and storage.

Correct Option: C

Insulin storage vesicles in humans and many other species contain high concentrations of Zn₂+ and Ca₂+ ions. Zinc plays an important role in insulin hexamerisation, which is closely related to some of the processes in insulin biosynthesis and storage.