Question

The network of air tubes in insects for gaseous exchange is known as?
A. Trachea
B. Spiracles
C. Stomata
D. Skin

Answer 1

Hint:
Insects have spiracles, that are openings on exoskeletons to allow air to enter the trachea. These are connected to tracheal tubes that deliver oxygen directly into the tissues of insects. The spiracles are usually one pair per body segment located laterally along the thorax and abdomen of most whereas the trachea forms a network of internal tubes.

Complete answer:
Option A is a trachea that is a part of the tracheal system which contains air-filled internal tubes. The tracheal system is used in Gaseous exchange in insects. This tracheal system further has finer branches that extend to all parts of the body and may become functionally intracellular in muscle fibers. Thus they carry oxygen in the gas phase directly to its sites of utilization.
Option B- spiracles. These are openings found on the outside of an insect's exoskeleton. They are used for breathing. There are numerous spiracles on the body of an insect, which are present in pairs on the thorax and abdomen.
OptionC is stomata- they are openings through which plants regulate water and CO2. Carbon uptake and transpiration are the two processes that are induced by stomata which facilitate the nutrient acquisition by gall tissue and phylloxera.
Option D is skin- Insects do not have skin like you, but instead, have a hard outer covering known as an exoskeleton that protects their organs and gives them support for moving around.

So, the correct answer option A i.e trachea.

Note: Insects respire or exchange oxygen and carbon dioxide between their tissues and the air by a system of air-filled tubes called tracheae. These Tracheae open to the outside through small holes called spiracles. Which helps in breathing. Tracheas also connects to ever-finer branches that penetrate to every part of the body. These are called tracheoles, they may be less than 1 µm in diameter.