What does below chemistry rebus means?

You enter your friend's room. He is not in his room. Although you see that on the bed there are two dogs, five cats, two giraffes and three pigs. Also, a couple of chickens and ducks are flying in the room.

Calculate the number of legs standing on the floor.

There are 2 people near the river and both of them want to get on the other side. The boat can only take one of them. But they got across.
How?

People put me on the table and cut me but do not eat me. What am I?

Make the seating arrangement of 10 children in such a way that there are 5 rows with 4 children in each row.

What have one eye but still cannot see?

Solve below rebus puzzle?

A patient was diagnosed with some ailment. He was given five different tablets to take at night at an interval of 15 minutes.

How long will it take the patient to consume all the five tablets?

What jumps when it walks and sits when it stands?

15 caves are arranged in a circle at the temple of doom. One of these caves has the treasure of gems and wealth. Each day the treasure keepers can move the treasure to an adjacent cave or can keep it in the same cave. Every day two treasure seekers visit the place and have enough time to enter any two caves of their choice.

How do the treasure seekers ensure that they find the treasure in the minimum number of possible days?