What is both possible and impossible at the same time?

I am looking for a word that change both gender and number when i add the letter 'S'.

What Word am I Looking For ?

There is a circular car race track of 10km. There are two cars, Car A and Car B. And they are at the exact opposite end to each other. At Time T(0), Both cars move toward each other at a constant speed of 100 m/seconds. As we know both cars are at the same speed they will always be the exact opposite to each other.
Note, at the center, there is a bug which starts flying towards Car A at time T(0). When the bug reaches car B, it turns back and starts moving towards the car A. The speed of bug is 1m/second. After 5 hours all three stop moving.
What is the total distance covered by the bug?

What is common among 11, 69, and 88?

My cousin lives in one story house in Antarctica. His house is made the of-of sandstone. what is the color of stairs?

Take one out and scratch my head, I am now black but once was red. What am I?

How many words can a pen with half refill write?

Which five letter word can be added at the end of below word to form a
valid word?

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Which fur should we be getting from the Lion?

Solve the puzzle by telling what does below picture means.