Questions

Giraffe has the highest blood pressure among animals. 

This is due to the fact that there is a large pressure drop (~100 mmhg) as the blood is transported from the heart, up the neck, to the brain. This is about twice the normal blood pressure of humans (120/80 mmhg).

Every year 5th September is celebrated as Teacher's Day in India, in the memory of Dr. Sarvepalli Radhakrishnan's birthday. He was the first vice-president and second president of India.

After he become the president of India, his students want to celebrate his birthday in grand but he refused and he adviced them to celebrate that day as teachers day. From then, 5th September is celebrated as Teacher's Day.

In the given options, "His stomach rumbled like an approaching train" is an example of Simile.

All the other options are examples of metaphors. 

Simile and Metaphor are both figure of speeches in English which are used for comparing things but the only difference is Simile uses LIKE or AS words in comparing and metaphor directly compares without using any words.