Page 20 - Biology Form Two

Biology for Secondary Schools

Roughage shape of cells, tissues, and organs. Water
This is dietary fibre that is obtained helps in the process of breaking down
from the indigestible part of plants food during digestion. It also lubricates
(Figure 1.7). Roughage does not have moving parts of the body and prevents
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any nutritional value as it is not digested friction. Additionally, water helps in
and absorbed in the body. Sources of the regulation of body temperature.
dietary fibre include cassava, potatoes, Sweating is one of the means by which
beans, fruits, cabbage, spinach, and water prevents the human body from
whole grain cereals. overheating during hot weather. This
is because evaporation of sweat from
Functions of roughage the surface of the skin helps the body
Roughage helps in the passage of food to cool during hot conditions. It is
and faeces through the gut by aiding important to drink enough safe water,
contraction and relaxation of the gut and eat raw vegetables and fruits to
muscles (peristalitic movement). It maintain an optimal water content in
also helps to control body weight, thus the body. A lacking of adequate water
protects the body from diseases such as in the body leads to thirst, dehydration
heart diseases. and constipation. Losing more than
10% of water in the body can lead to
death.

Balanced diet

Task 1.3
Search for information from the library

and internet sources on concept of a
balanced diet. Then, summarise your
findings.
Figure 1.7: Sources of roughage
A balanced diet refers to a meal
Water containing foods from all food groups
Water is an essential nutrient for the in the right proportions. A proper diet
human body as it is a major constituent helps an individual to remain healthy.

of body fluids such as blood, tears, and For young individuals, a balanced
saliva. It forms a large part of the cell diet helps them to grow and develop
cytoplasm and helps to maintain the normally. It also help them to maintain

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