Chlorofluorocarbons (CFCs) released into the air, go up and react with the ozone, destroying it gradually.The destruction of ozone layer will allow the extremely harmful ultraviolet radiations of the sun to reach the earth. This causes skin cancer, cataract and destruction of plants including crops.

The increased level of nutrients in the water increases the growth of algae. Once these algae dies, they serve as food for decomposers like bacteria. A lot of oxygen is utilised in this process, consequently leading to a decrease in the level of Dissolved Oxygen (DO) in the waterbody. This, in turn causes fishes and other aquatic organisms to die.

Clear, transparent water is not always fit for drinking as it may have many disease carrying microbes and dissolved impurities that are not visible to unaided eyes. So, transparent water also needs to be purified by various processes.

(a) Adrenaline is secreted from adrenal gland during the stress conditions like fright or fear, anger, worry or embarrassment.
(b) Growth hormone is secreted from pituitary gland to regulate the normal growth of a person, i.e. growth of a child to adult.
(c) Insect hormones control the development of caterpillar to moth.
(d) Thyroxine is produced by thyroid gland to control the development of tadpole to frog.

(a) This process is known as menstruation (in scientific terms).
(b) The human female have said to attain puberty.
(c) The onset of this process signify that the reproductive system of human female has started working.
(d) During pregnancy, this process stops temporarily.
(e) Menopause is the term used when this process stops permanently.

Lila's diet is not a balanced diet because her meal does not contain the adequate nutritional requirement. She takes only proteins and carbohydrates in every meal. She requires vitamins and minerals in her meal to protect her from various diseases. Thus, I would suggest her to include fruits and vegetables in her meal as a source of vitamins and minerals.

The Ganga is the Indian holy river that is amongst the ten most endangered rivers list of WWF. The water has been highly polluted because the towns and cities through which the river flows, throw huge quantities of garbage, untreated sewage, dead bodies and many other harmful things, directly into the river. In fact, the river is dead at many places where the pollution levels are extremely high.

(a) Pituitary gland It releases hormones that control the release of sex hormones, i.e. testosterone in males and oestrogen in females.
(b) Testis It releases testosterone which is responsible for the secondary sexual character in boys.
(c) Pancreas It releases insulin which prevents diabetes.
(d) Adrenal gland It releases aldosterone that maintains the correct salt balance in the blood