Consider the following statements about the skeletal system: 1. Bones store calcium and phosphorus. 2. Red bone marrow produces blood cells. 3. Ligaments connect muscle to bone. Which of the above is/are correct? MCQ with Answer and Explanation
Consider the following statements about the skeletal system:
1. Bones store calcium and phosphorus.
2. Red bone marrow produces blood cells.
3. Ligaments connect muscle to bone.
Which of the above is/are correct?
A. 1, 2, and 3
B. 1 and 2 only
C. 1 and 3 only
D. 2 and 3 only
Answer: Option B
Solution (By JKExamLibrary)
Bones store minerals (1) and contain marrow for hematopoiesis (2). Ligaments connect bone to bone; tendons connect muscle to bone. So 3 is incorrect.
Consider the following statements about the human kidneys:
1. They are located in the abdominal cavity.
2. They produce the hormone renin.
3. They filter approximately 180 liters of blood per day.
Which of the above is/are correct?
Explanation:
Kidneys are retroperitoneal, not in the abdominal cavity proper. They produce renin, and filter ~180 L/day (GFR ~125 mL/min). So 1 is incorrect.
Explanation:
Selman Waksman, who discovered streptomycin, coined the term 'antibiotic' in 1942 to describe chemical substances produced by microorganisms that inhibit or kill other microorganisms. Fleming discovered penicillin but did not coin the term. Pasteur developed pasteurization and rabies vaccine, Ehrlich discovered salvarsan (magic bullet) for syphilis.
Assertion (A): Fishes are ammonotelic.
Reason (R): Ammonia is highly toxic and requires a large amount of water for excretion, which is available in aquatic environments.
A.Both A and R are true, but R is not the correct explanation.
B.A false, R true.
C.A true, R false.
D.Both A and R are true, and R is the correct explanation.
Explanation:
Ammonotelic organisms excrete ammonia directly into water, which dilutes it. This is feasible for fishes. The reason correctly explains why they are ammonotelic.
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