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1. Choose the correct option from the following.

1. Choose the correct option from the following.

a. Suhani’s finger got injured and started bleeding while trimming a pencil. Which component of blood cells will stop the blood flow by forming a clot?
i. Plasma
ii. WBCs
iii. RBCs
iv. Platelets

Answer: iv. Platelets

b. Life span of leucocytes is about:
i. 1-2 days
ii. 3-5 days
iii. 2-3 days
iv. 13-20 days

Answer: iv. 13-20 days

c. The loss of water from the leaves into the air in the form of vapour is called:
i. absorption
ii. transpiration
iii. excretion
iv. elimination

Answer: ii. transpiration

d. Which part of the human body converts ammonia to urea to be excreted in urine?
i. Lungs
ii. Stomach
iii. Liver
iv. Kidneys

Answer: iii. Liver

2. Assertion-Reasoning questions.

(i) Assertion (A): Blood appears red in colour.
Reason (R): Red blood cells present in blood contain haemoglobin.(a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
Explanation: The Assertion is true because blood is red. The Reason is also true and correctly explains the Assertion: the haemoglobin protein in Red Blood Cells is red in colour, which gives blood its distinctive appearance

(ii) Assertion (A): Reptiles are considered as uricotelic animals.
Reason (R): Reptiles excrete waste majorly in the form of uric acid.

• (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
  Explanation: Both statements are factually correct. The term “uricotelic” is defined by the excretion of uric acid as the primary nitrogenous waste, so the Reason perfectly explains the Assertion.
• 3. Answer the following questions in one sentence.
• a. What is the act of voluntarily giving blood for transfusion called?
• It is called blood donation.
• b. Amoeba do not have well-defined excretory systems. By which process do they get rid of body wastes?
• They get rid of body wastes through the process of diffusion.
• c. What is the phase of relaxation of heart muscles during a heartbeat called?
• It is called diastole.
• d. Name a crystalline waste product found in the leaves and stems of plants like rhubarb and water hyacinth.
• Calcium oxalate crystals

4. Answer the following questions in 2-3 sentences.

a. Differentiate between hematuria and dysuria.

• Hematuria is a condition where there is blood in the urine. Dysuria is a condition characterized by pain, discomfort, or a burning sensation during urination.

b. What is the function of the urethra in the human body?

• The urethra is a tube that carries urine from the urinary bladder to the outside of the body. In males, it also serves as a passage for semen during ejaculation.

5. Answer the following questions in 3-4 sentences.

a. State any three situations that require a blood transfusion.

• Three situations that require a blood transfusion are:

1. Severe blood loss: Due to a major injury, accident, or during surgery.
2. Medical conditions: Like severe anaemia (low red blood cell count) or thalassemia.
3. Cancer treatments, such as chemotherapy, can reduce blood cell production.

b. What happens to the rate of transpiration if:
i. The temperature of a place increases?

• The rate of transpiration increases because higher temperatures cause water to evaporate more quickly from the leaf surfaces.

ii. humidity of a place increases?

• The rate of transpiration decreases because high humidity means the air already contains a lot of water vapour, reducing the difference in water concentration between the leaf and the air.

iii. wind speed of a place decreases?

• The rate of transpiration decreases because slow-moving air allows a layer of humid air to stay around the leaf, which slows down further water loss.