What am I riddles for kids with simple answers

It can't be seen, can't be felt, can't be heard and can't be smelt. It lies behind stars and under hills, and empty holes it fills. It comes first and follows after, ends life and kills laughter. What is it?

I live in the ocean. I have eight legs, two big claws and a tail. My body has a hard shell. I eat anything I can find. I am a...

I eat, I live. I breathe, I live. I drink, I die. What am I?

I am pronounced as a one letter alphabet. I am written with three letters. I am complete with just two letters. I am double. I am blue I am black I am brown I am gray I am yellow and I am green. I can read from both ends. I appear the same every way! What am I?

Born of water, I drown in water. A blood-thirsty beast you can barely see. What am I?

I can only live where there is light, but I die if the light shines on me. What am I?

I have a bed but I do not sleep. I have a mouth but I don't eat. You hear me whisper, but I never talk. You can see me run, yet I never walk. What am I?

A mirror for the famous, but informative to all. I'll show you the world, but it may be a bit small. What am I?

I repeat only the last word you say. The more I repeat, the softer I got. I cannot be seen but can be heard. What am I?

Sometimes I am loved, usually by the young. Other times I am dreaded, mostly by the old ones. I am hard to remember, also hard to forget. And yet if you do, You'll make someone upset. I occur every day everyone has to face me. Even if you don't want it to happen; embrace me. What am I?