Excretory Products and Their Elimination MCQs for NEET — Zoology Questions with Answers

The assertion (A) states that the utilization of water and consumption of energy for elimination of waste products are inversely proportional, which is true. The reason (R) states that ammonia is less toxic and can be eliminated with a large amount of water, which is false. Ammonia is actually highly toxic and requires a large amount of water for its elimination, hence (A) is true and (R) is false.

The main excretory units in cockroaches are Malpighian tubules. These tubules are responsible for the removal of waste products from the hemolymph (the insect's blood) and their excretion into the digestive tract, where they are expelled from the body.

In Periplaneta (the common cockroach), the Malpighian tubules are located at the junction of the midgut and hindgut, and there are about 150 of them. These tubules play a crucial role in the excretory system, helping to remove waste products from the hemolymph.

In cockroaches, the Malpighian tubules are yellow in color, and their free (distal) end is blind. These tubules float freely in the hemolymph and are responsible for the excretion of nitrogenous wastes.

The wall of each Malpighian tubule in cockroaches is lined with glandular and ciliated cells. The glandular cells are involved in secretion, while the ciliated cells help in propelling the waste materials through the tubules.

In cockroaches, the Malpighian tubules are responsible for the excretion of waste products. These tubules collect waste materials from the haemolymph and then release them into the hindgut, where they are eventually excreted out of the body. The hindgut includes the ileum, colon, and rectum, which are parts of the digestive system involved in the excretion process.

Cockroaches are uricotelic animals, meaning they excrete nitrogenous waste primarily in the form of uric acid. Uric acid is relatively non-toxic and requires less water for excretion, making it an advantageous adaptation for terrestrial insects like cockroaches that need to conserve water.

Cockroaches primarily excrete uric acid. This method of excretion is known as uricotelism, which is an adaptation to conserve water. Uric acid is less toxic and less soluble in water compared to other nitrogenous wastes like urea and ammonia, making it an efficient waste product for terrestrial animals like cockroaches.

Cockroaches secrete uric acid as their primary nitrogenous waste. This is typical of uricotelic organisms, which include many insects, birds, and reptiles. Uric acid is a less toxic form of nitrogenous waste and requires minimal water for excretion, which is advantageous for survival in terrestrial habitats.