The intercostal muscles that run between the ribs are not fully developed until a child reaches school age. This can make it difficult to lift the rib cage especially when lying. a. True
b. False

True

Explanation:

Intercostal muscles are groups of muscles that run between the ribs, and help form the chest wall. The intercostal muscles are mainly involved in moving the chest wall up and down thereby expanding and shrinking the size of the chest cavity during the process of breathing through their contraction and relaxation.

In adults, the coordinated activity of three muscle groups, the diaphragm, intercostal muscles and the abdominal muscles facilitates breathing. The contraction and relaxation of the diaphragm helps in filling and expulsion of air from the lungs. The intercostal muscles facilitates chest movement, while the abdominal muscles help to push the diaphragm up thereby pushing air out of the lungs.

However, in babies and young children, the intercostal muscles are not fully developed, therefore, they will use their abdominal muscles much more to pull the diaphragm down for breathing. This can make it difficult to lift the rib cage especially when lying. The intercostal muscles will not be fully developed until about the age of ten years in a child. Thus, a child is more susceptible to respiratory problems than an adult.

affects the water bodies: excessive use of fertilizers causes eutrophication. the fertilizers which are used on plants affect the quality of land on which it is used, further causing erosion of soil. the fertilizers used on plants contain harmful chemical fumes which affect the environment.