The valve that prevents backflow from the right ventricle into the right atrium is the: MCQ with Answer and Explanation

The valve that prevents backflow from the right ventricle into the right atrium is the:
A. Pulmonary valve
B. Aortic valve
C. Bicuspid valve
D. Tricuspid valve
Answer: Option D
Solution (By JKSSB Mock Tests)
The tricuspid valve (right atrioventricular valve) has three cusps and closes during ventricular systole to prevent regurgitation into the right atrium. The bicuspid (mitral) is on the left side. Aortic and pulmonary valves are semilunar valves at the ventricular outlets.

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Question #1
The instrument used to measure blood pressure is a:
A. Electrocardiograph
B. Sphygmomanometer
C. Thermometer
D. Stethoscope

Correct Answer: Option B


Explanation:
A sphygmomanometer, often used with a stethoscope, measures arterial blood pressure (systolic/diastolic) in mmHg. A stethoscope listens to heart/lung sounds, thermometer measures temperature, ECG records heart electrical activity. Normal blood pressure is about 120/80 mmHg.

This question belongs to: Science Biology
Question #2
In a dihybrid cross between two heterozygous pea plants (RrYy x RrYy), if the two genes are completely linked, the phenotypic ratio in the F2 generation will be:
A. 9:3:3:1
B. 3:1
C. 1:2:1
D. 1:1:1:1

Correct Answer: Option B


Explanation:
If two genes are completely linked, they are located very close together on the same chromosome and do not undergo independent assortment or crossing over. They are inherited together as a single unit. A dihybrid cross (RrYy x RrYy) with complete linkage behaves like a monohybrid cross. The F1 produces only parental gametes (RY and ry). The F2 generation will have a genotypic ratio of 1 RRYY : 2 RrYy : 1 rryy, resulting in a phenotypic ratio of 3:1.

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Question #3
The hormone that stimulates the kidney to convert 25-hydroxyvitamin D to active 1,25-dihydroxyvitamin D is:
A. ACTH
B. TSH
C. Calcitonin
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Correct Answer: Option D


Explanation:
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