Science
Respiratory structures of two different animals — a fish and a human being are as shown.
Observe (a) and (b) and select one characteristic that holds true for both of them.
- Both are placed internally in the body of animal.
- Both have thin and moist surface for gaseous exchange.
- Both are poorly supplied with blood vessels to conserve energy.
- In both the blood returns to the heart after being oxygenated.
Related Questions
Assertion (A): Hydrochloric acid helps in the digestion of food in the stomach.
Reason (R): Hydrochloric acid creates an acidic medium to activate protein digesting enzymes.
- Both A and R are true, and R is the correct explanation of A.
- Both A and R are true, and R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
A student was asked to write a stepwise procedure to demonstrate that carbon dioxide is necessary for photosynthesis. He wrote the following steps. The wrongly worded step is:
- Both potted plants are kept in dark rooms for at least three days.
- Bottom of the bell jars is sealed to make them air tight.
- Both potted plants are kept in sunlight after the starch test.
- A leaf from both the plants is taken to test the presence of starch.
If a lens can converge the sun rays at a point 20 cm away from its optical centre, the power of this lens is –
- +2D
- –2D
- +5D
- –5D
Observe the diagram of an activity given below. What does it help to conclude, when the person exhales into the test-tube?
- Percentage of carbon dioxide is more in inhaled air.
- Fermentation occurs in the presence of oxygen.
- Percentage of carbon dioxide is more in exhaled air.
- Fermentation occurs in presence of carbon dioxide