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

You are confined in a room and given two metal rods. Out of these two rods, one is magnet and the other is the iron rod. They look starkly similar. You don't have any other metal object in the room.

How will you decide which one of those is magnet?

I am a type of vehicle that has two wheels and is powered by humans. What am I?
Hint 1: You can ride me for exercise.
Hint 2: I am environment-friendly.

Complete the table series riddle by finding the number that can replace "??".

Count the number of times the letter "F" appears in the following paragraph:

FAY FRIED FIFTY POUNDS OF
SALTED FISH AND THREE POUNDS
OF DRY FENNEL FOR DINNER FOR
FORTY MEMBERS OF HER FATHER'S FAMILY.

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

What does this rebus riddle mean?

How is a fly different from a mosquito?

By using 'because' continuously three times, can you make an English statement ?

Why do we preferably have round manhole covers and not square ones?