I have no doors but I have keys, I have no rooms but I have space, you can enter but you can’t leave! What am I?

Two guards were guarding the camp.Guard-1 was looking towards the south to make sure no threat is coming from the road.Guard-2 was looking at the north to make sure no threat is coming from the top. Suddenly Guard-1 ask the Guard-2 why he is smiling?How Guard-1 knows that Guard-2 is smiling?

What is wrong in the below Picture?

What is in seasons, seconds, centuries and minutes but not in decades, years or days?

Two in a corner, one in a room, zero in a house, but one in a shelter. What am I?

There are nine dots in the picture that has been attached with this question. Can you join all the dots by drawing four straight lines without picking up your pen?

Can you find the missing letter in the sequence?
S - T - I - L - ? - T - F - Y - C

Can you identify the hidden rebus in the image below?

I’m light as a feather, yet the strongest person can’t hold me for five minutes. What am I?

My grandson is about as many days as my son in weeks, and my grandson is as many months as I am in years. My grandson, my son and I together are 120 years. Can you tell me my age in years ?