What is common to whales, seals and sharks?

The correct option is D

Convergent evolution

The correct answer is Option D.

Explanation of the correct answer:

1. Whales, seals, and sharks are marine and spend their entire lives in oceans.
2. Thus, they have developed some similar organs.
3. Appendages in whales, seals, and sharks are fin-shaped which helps in pushing through the water.
4. The bodies of whales, seals, and sharks are streamlined and smooth.
5. Whales, seals, and sharks have a single tail fin which is used for propulsion.
6. These similar methods in whales, seals, and sharks for locomotion are examples of convergent evolution.

Explanation of the incorrect options:

Option A: Thick subcutaneous fat is the fat found under the skin. Thick subcutaneous fat is not common in whales, seals and sharks.

Option B: Homoiothermy is a phenomenon in which the temperature of the body of the organism is constant irrespective of the temperature of the surrounding. Whales, seals and sharks are not homoiotherms.

Option C: Seasonal migration is movement from one place to another on the basis of season. Seasonal migration is not seen in whales, seals and sharks.

Final answer: Convergent evolution common to whales, seals and sharks.