CG Board Class 7 Science Excretion in the Living Organisms Textbook fill in the blanks and question answers.
Choose the correct answer
1. Unwanted substances are filtered from the blood by
a) Heart b) Lungs c) Kidney d) Stomach
Correct Answer: c) Kidney
2. The main excretory substance in man is
a) Uric acid b) Urea c) Water d) Sweat
Correct Answer: b) Urea
3. In bird droppings the colour of uric acid is
a)Black b) White c) Green d) Green & White
Correct Answer: a) White
4. In our body, which organ is responsible for conversion of ammonia to urea
a)Liver b) Kidney c) Lungs d) Heart
Correct Answer: a) Liver
5. In which organism does ammonia get directly dissolved in water through the body surface.
a)Mosquito b) Parrot c) Lizard d) Amoeba
Correct Answer: d) Amoeba
Answer the following questions
1. Why it is necessary to remove unwanted metabolic products from the body?
Unwanted metabolic products can be toxic, and their accumulation can harm the body’s functioning. Excretion helps maintain a healthy internal environment.
2. Where are the kidneys situated?
The kidneys are situated just below the diaphragm, inside the abdomen, on either side of the vertebral column.
3. How is urine formed?
Urine is formed through the filtration of blood by the kidneys. The kidneys filter out waste products and excess substances, which are then excreted as urine.
4. Name some of the excretory substances formed in plants.
Excretory substances in plants include calcium oxalate or calcium carbonate crystals, such as raphides found in yam and Colocasia leaves.
5. How does excretion takes place in birds and insects?
Birds excrete uric acid, which is a solid substance, along with feces. Insects also excrete solid uric acid, and their waste products are eliminated through specialized structures like Malpighian tubules.
