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

What does this rebus mean?

O
N
C
E
TIME

If you read clockwise, you can form a word by inserting three missing letters in the picture given below. Can you do it?

What does below science rebus mean?

Ag Ag Ag
Ag SPOON Ag
Ag Ag Ag

They do not possess flesh or feathers or scales or bone
But still, they are blessed with fingers and thumbs of their own.

Spot 5 differences in two Christmas tree below:

Samuel was out for a walk when it started to rain. He did not have an umbrella and he wasn't wearing a hat. His clothes were soaked, yet not a single hair on his head got wet. How could this happen?

Which of the following words don't belong in the group and why?
CORSET, COSTER, SECTOR, ESCORT, COURTS

For an extra income, John decided to work at a Hotel for one hour daily. The manager offers him that they will pay him $11 after every 11 days.
However, John offered a different proposition to the manager. The offers stand as:
He will be paid just a penny on his first day.
Two pence will be paid on the second day,
Four pence will be paid on the third day.
And so on till the 11th day.

Should the Hotel manager accept his offer?

Can you count the number of triangles in the given figure?