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

Living above a star, I do not burn
Eleven friends and they do not turn
I can just be visited in a sequence, not once or repeatedly
PQRS are my initials
Can you tell my name accurately?

It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?

What runs around the whole yard without moving?

What has 88 keys?

If there are fifteen crows on a fence and the farmer shoots a third of them, how many crows are left?

A shepherd had 18 sheep, out of which, all but ten died.

Can you tell us how many sheep was he left with?

_ _ _ IE _ _
_ _ _ IE _
_ _ IE _ _
_ _ IE _
_ _ _ _ IE

Like you see, some letters have gone missing from these words that contain the IE pair at some or the other place. The letters that will be used to fill the blanks are given below. Use them and form meaningful words. Can you do that?

A, C, D, F, H, K, L, M, N, N, O, R, R, S, S, S, T, T, Y and Y.

What English word has three consecutive double letters?

I am the first thing you need while camping.
I am always with the person named Marcos Valencia and Carrick.
But Pogba Zlatan and Rooney think I am wasteful and do not need me.
I am the second to the last thing to add when you are making a patch.

What am I?