Biology Questions

Polygenic inheritance involves the determination of a particular phenotypic characteristic by many genes, called polygenes(group of genes influencing a quantitative characteristic), each having a small effect individually.

Height and skin colour in humans are examples of Polygenic characters.

The organs protected by the thoracic cage include the lungs and the heart.

The kidneys are stimulated to produce renin by a decrease in the blood pressure.

The renin-angiotensin system or RAS regulates blood pressure and fluid balance in the body. When blood volume or sodium levels in the body are low, or blood potassium is high, cells in the kidney release the enzyme, renin. Renin's primary function is therefore to eventually cause an increase in blood pressure, leading to restoration of perfusion pressure in the kidneys.

ACTH means Adrenal Corticotrophic Hormone.

CRH - Corticotrophin Releasing Hormone produced by hypothalamus stimulates the pituitary gland to release the ACTH which in turn produces corticosteroid hormones by adrenal glands.

Hence, the given statement is TRUE.

The oval window is connected directly to scala vestibuli.

In the above given options, Retrovirus is the only virus which is not associated with cancer. Here the viruses which are associated with different types of cancer. They are:

Hepatitis virus which is associated with Liver cancer

Papillomavirus which is associated with Cervical cancer

Epstein-Barr virus which is associated with Burkitt's lymphoma.

Sexual reproduction results in gametes that combine two cells from different individuals. Meiosis also produces gametes. Haploids contain one set of chromosomes in each of their cells. Diploids cells contain two chromosome sets. For plants, haploid and diploid cells divide via mitosis. The plants’ haploid phase is called the gametophyte, and the diploid phase is called the sporophyte.

Sporophytes are diploid plants that use meiosis to produce spores. These spores are haploid cells that grow into haploid gametophytes. Megaspores grow into female gametophytes, and microspores grow into male gametophytes.

Gametophytes are haploid plants that use mitosis to make haploid gametes. These gametes are female in the form of an ovum (egg) or male in the form of sperm.