Can anyone tell me a word in the English dictionary which has a silent 'z'?

Which is faster, Heat or Cold ? Explain.

He runs but never walks. Murmurs, but never talks. Has a bed, but never sleeps. And has a mouth, but never eats?

I have four wings but can't fly.
I express no emotions.
I am found on the exact spot every time you look.
I keep toiling away with a little sound.

Do you know what am I?

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

Decode the below four famous ciphers:

8P of the SS
1M of the E
1S of the SS
60M in 1H

A four-digit number (not beginning with 0) can be represented by ABCD. There is one number such that ABCD=A^B*C^D, where A^B means A raised to the B power. Can you find it?

Can you find the missing piece of the Porsche?

I’m tall when I’m young, and I’m short when I’m old. What am I?

1. How can we put an elephant in the refrigerator?
2. How can we put a Giraffe in a refrigerator?
3. The king of the jungle invites all the animals to a party everyone comes except for one animal, which animal?
4. You come to a crocodile-infested lake, you can't go around it, you can't co under it and you can't go over it, how do you get across?