All the components of the nodal tissue are autoexcitable. Why does the SA node act as the normal pacemaker?
| 1. | SA node has the lowest rate of depolarisation |
| 2. | SA node is the only component to generate the threshold potential. |
| 3. | Only SA node can convey the action potential to the other |
| 4. | SA node has the highest rate of depolarisation. |
A specialised nodal tissue embedded in the lower corner of the right atrium, close to atrio-ventricular septum, delays the spreading of impulses to heart apex for about 0.1 sec.
This delay allows -
1. blood to enter aorta.
2. the ventricles to empty completely.
3. blood to enter pulmonary arteries.
4. the atria to empty completely.
Match the following parts of a nephron with their function:
| (a) | Descending limb of Henle's loop | (i) | Reabsorption of salts only |
| (b) | Proximal convoluted tubule | (ii) | Reabsorption of water only |
| (c) | Ascending limb of Henle's loop | (iii) | Conditional reabsorption of sodium ions |
| (d) | Distal convoluted tubule | (iv) | Reabsorption of ions, water, and organic nutrients |
Select the correct option from the following:
| Options: | (a) | (b) | (c) | (d) |
| 1. | i | iii | ii | iv |
| 2. | ii | iv | i | iii |
| 3. | i | iv | ii | iii |
| 4. | iv | i | iii | ii |
Match the items in Column - I with those in Column - II:
| Column I | Column II | ||
| (a) | Podocytes | (i) | Crystallised oxalate |
| (b) | Protonephridia | (ii) | Annelids |
| (c) | Nephridia | (iii) | Amphioxus |
| (d) | Renal calculi | (iv) | Filtration slits |
| (a) | (b) | (c) | (d) | |
| 1. | (iii) | (iv) | (ii) | (i) |
| 2. | (iii) | (ii) | (iv) | (i) |
| 3. | (iv) | (iii) | (ii) | (i) |
| 4. | (iv) | (ii) | (iii) | (i) |
Which of the following receptors are specifically responsible for maintenance of balance of body and posture?
1. Basilar membrane and otoliths
2. Hair cells and organ of corti
3. Tectorial membrane and macula
4. Crista ampullaris and macula
Which of the following is against the rules of ICBN?
| 1. | Handwritten scientific names should be underlined separately. |
| 2. | Every species should have a generic name and a specific epithet. |
| 3. | Scientific names are in Latin and should be italicized. |
| 4. | Generic and specific names should be written starting with small letters. |
Mad cow disease in cattle is caused by an organism which has:
1. Inert crystalline
2. Abnormally folded protein
3. Free RNA without protein coat
4. Free DNA without protein coat
Which of the following statements is correct?
1. Lichens do not grow in polluted areas.
2. Algal component of lichens is called mycobiont.
3. Fungal component of lichens is called phycobiont.
4. Lichens are not good pollution indicators.
Match the organisms in Column-I with habitats in Column-II.
| Column-I | Column-II | ||
| (a) | Halophiles | (i) | Hot springs |
| (b) | Thermoacidophiles | (ii) | Aquatic environment |
| (c) | Methanogens | (iii) | Guts of ruminants |
| (d) | Cyanobacteria | (iv) | Salty areas |
Select the correct answer from the options given below:
| Options: | (a) | (b) | (c) | (d) |
| 1. | (iv) | (i) | (iii) | (ii) |
| 2. | (i) | (ii) | (iii) | (iv) |
| 3. | (iii) | (iv) | (i) | (i) |
| 4. | (ii) | (iv) | (iii) | (i) |
In the dicot root, the vascular cambium originates from:
| 1. | Tissue located below the phloem bundles and a portion of pericycle tissue above protoxylem |
| 2. | Cortical region |
| 3. | Parenchyma between endodermis and pericycle |
| 4. | Intrafascicular and interfascicular tissue in a ring |
© 2026 GoodEd Technologies Pvt. Ltd.