What has one letter and starts with an E?

I am a type of food that is often found in the fridge and can be white in colour. What I am?
Hint 1: I am a dairy product.
Hint 2: You can spread me on the bread.

I always drive my customer away.

Who am I?

Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?

What demands an answer, but asks no questions

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?

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

Complete the following series. It.s very logical:

1, 4, 5, 6, 7, 9, 11, __?

Look at the picture and find out which square is not linked with any of the other squares.