Question

Fish breathe with the help of gills which are richly supplied with blood vessels. The gills help the fish to:

• A. take in oxygen from the air
• B. take in oxygen dissolved in water
• C. absorb nutrients present in water
• D. release waste substances in water

Answer 1

The correct option is B

take in oxygen dissolved in water

The correct option is option B:

Explanation of the correct option:

1. Fish in any type of aquatic environment require oxygen to survive.
2. The gills are structures that allow them to breathe underwater by exchanging gases. For this reason, they have an abundance of blood vessels.
3. Gills are positioned next to the mouth cavity of fish.
4. Fish use their mouths to draw oxygen-rich water in and pump it over their gills.
5. Most fish have a skin flap that protects their gills. They help with the gas exchange by absorbing oxygen dissolved in the water.

Explanation of the incorrect option:

Option A:

1. Fish does not take oxygen from the air.
2. Fish take oxygen from the water through gills.

Option C:

1. Gills do not play any role in mineral absorption.
2. Fish absorbs mineral from the food they eat.
3. Nutrients are absorbed in the small intestine.

Option D:

1. Gills do not play any role in the excretion of waste material from fish.
2. Fish excrete the waste material through the kidney that goes out through the urinary pore.

Final answer: Fish breathe with the help of gills which are richly supplied with blood vessels. The gills help the fish to take in oxygen dissolved in water.