Biology Questions and Answers

The testis is a male reproductive organ in humans. It is responsible for producing sperm cells and secreting the male sex hormone testosterone. The testes are located within the scrotum, outside the abdominal cavity.

The theory of evolution is a scientific explanation for the diversity of life on Earth. It states that species change over time through a process known as natural selection. This theory, proposed by Charles Darwin and Alfred Russel Wallace in the 19th century, suggests that populations of organisms evolve over generations in response to changes in their environment.

Autotrophic nutrition refers to the ability of organisms to synthesize their own food molecules from simple inorganic substances such as carbon dioxide and water.

Nitrogen fixation: This process involves the conversion of atmospheric nitrogen gas (N2) into a usable form, such as ammonium (NH4+), by nitrogen-fixing bacteria or through lightning. This makes nitrogen available for plants and other organisms.

Denitrification: Denitrifying bacteria convert nitrates (NO3-) back into atmospheric nitrogen gas (N2), completing the nitrogen cycle. Denitrification occurs under anaerobic conditions, such as in waterlogged soils or sediments.

Ammonification: Ammonification is the process by which decomposers, like bacteria and fungi, break down organic nitrogen compounds from dead organisms and waste products into ammonium (NH4+). This ammonium can then be used by plants and other organisms.

Sexual reproduction involves the fusion of gametes from two parents, typically a male and a female. In this process, specialized cells called gametes (sperm and egg) are produced through meiosis. The fusion of these gametes during fertilization leads to the formation of a zygote, which develops into a new individual with a combination of genetic traits from both parents.

Laterite soil becomes less fertile due to intense leaching caused by tropical rains. Leaching is the process by which nutrients are washed out of the soil by rainfall. In the case of laterite soils, which are common in tropical regions, the heavy rainfall can cause intense leaching, leading to a loss of fertility.

The skin plays a vital role in maintaining homeostasis by regulating body temperature. When the body becomes too hot, the skin helps to cool it down through processes like sweating and vasodilation.

Nitrogen fixation is the process in the nutrient cycle that converts atmospheric nitrogen (N2) into a form that plants can utilize, typically ammonium (NH4+) or nitrate (NO3-). This process is carried out by nitrogen-fixing bacteria, which can either be free-living in the soil or form mutualistic relationships with certain plants, such as legumes.

The natural place of an organism or community is known as its habitat. A habitat is an ecological or environmental area that is inhabited by a particular species of animal, plant, or other type of organism. It is the natural environment in which an organism lives, or the physical environment that surrounds a species population.

Aestivation: Certain animals enter a state of estivation, which is similar to hibernation but occurs in response to hot and dry conditions. They become inactive, conserve energy, and reduce water loss during the hottest parts of the day or during extended periods of high temperatures.