Q. No.Consider the given two statements:
| Assertion (A): | In frogs, blood from the lungs and body is mixed in the ventricle. |
| Reason (R): | Frogs have a three-chambered heart with one ventricle receiving both oxygenated and deoxygenated blood. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | (A) is False but (R) is True. |
Subtopic: Â Circulatory Pathways |
 95%
Level 1: 80%+
Please attempt this question first.
Hints
Please attempt this question first.
Given below are two statements:
| Assertion (A): | Cardiac muscle is auto excitable |
| Reason (R): | Nodal musculature of heart has the ability to generate action potentials without external stimuli |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | Both (A) and (R) are False. |
Subtopic: Â Circulatory Pathways |
 94%
Level 1: 80%+
Please attempt this question first.
Hints
Please attempt this question first.
Three chamber heart of frog is not as efficient as four chambered human heart because :-
1. Oxygenated and deoxygenated blood mix up
2. Ventricle does not pump blood properly
3. It does not hold enough blood
4. Heart muscles are not strong
Subtopic: Â Circulatory Pathways |
 94%
Level 1: 80%+
Please attempt this question first.
Hints
Please attempt this question first.
Single circulation is characteristic of
1. Fish heart
2. Frog heart
3. Crocodilian heart
4. Marsupial heart
Subtopic: Â Circulatory Pathways |
 93%
Level 1: 80%+
Please attempt this question first.
Hints
Please attempt this question first.
The sinoatrial node, which generates the electrical impulses that coordinate heart-muscle contractions, is located in the
1. medulla oblongata.
2. inferior (or posterior) vena cava.
3. right atrium.
4. left ventricle.
1. medulla oblongata.
2. inferior (or posterior) vena cava.
3. right atrium.
4. left ventricle.
Subtopic: Â Circulatory Pathways |
 93%
Level 1: 80%+
Please attempt this question first.
Hints
Please attempt this question first.
Consider the given two statements:
Options:
| Statement I: | Fishes possess a two-chambered heart with an atrium and a ventricle, where deoxygenated blood is pumped to the gills for oxygenation. |
| Statement II: | Birds and mammals possess a four-chambered heart, which ensures complete separation of oxygenated and deoxygenated blood. |
| 1. | Both Statement I and Statement II are correct. |
| 2. | Statement I is correct but Statement II is incorrect. |
| 3. | Statement I is incorrect but Statement II is correct. |
| 4. | Both Statement I and Statement II are incorrect. |
Subtopic: Â Circulatory Pathways |
 91%
Level 1: 80%+
Please attempt this question first.
Hints
Please attempt this question first.
The main advantage of a closed circulatory system, as seen in annelids and chordates, is:
| 1. | Blood is circulated more quickly, more precisely and at higher pressure to the organs. |
| 2. | Blood directly bathes the tissues, facilitating faster diffusion of gases. |
| 3. | Nutrients and waste are exchanged more efficiently in open spaces. |
| 4. | The heart does not require chambers for efficient circulation. |
Subtopic: Â Circulatory Pathways |
 90%
Level 1: 80%+
Please attempt this question first.
Hints
Please attempt this question first.
In a closed circulatory system, blood is completely enclosed within
1. the skeleton.
2. sinuses.
3. vessels.
4. hearts.
1. the skeleton.
2. sinuses.
3. vessels.
4. hearts.
Subtopic: Â Circulatory Pathways |
 89%
Level 1: 80%+
Please attempt this question first.
Hints
Please attempt this question first.
Which chambers of the heart pump oxygenated blood?
1. The right and left atria
2. The right and left ventricles
3. The right atria and the left ventricle
4. The left atria and the left ventricle
1. The right and left atria
2. The right and left ventricles
3. The right atria and the left ventricle
4. The left atria and the left ventricle
Subtopic: Â Circulatory Pathways |
 89%
Level 1: 80%+
Please attempt this question first.
Hints
Why do higher animals like mammals and birds possess a closed circulatory system instead of an open one?
| 1. | Because it allows blood to come in direct contact with tissues for faster absorption of oxygen |
| 2. | Because closed circulation prevents blood from reaching vital organs |
| 3. | Because open circulation is too complex for warm-blooded animals |
| 4. | Because a closed system permits more efficient nutrient and gas exchange through capillaries under controlled pressure |
Subtopic: Â Circulatory Pathways |
 88%
Level 1: 80%+
Please attempt this question first.
Hints
Please attempt this question first.
© 2026 GoodEd Technologies Pvt. Ltd.