Which of the eight images will fill the missing image in the puzzle below?

What is at the end of a rainbow?

I look at you, you look at me, I raise my right, you raise your left. What am I?

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

I have eight fingers and two thumbs but I do not live. What Am I?

There is one thing that goes round the house and also inside the house but never even share a brief touch. What is it?

If you’ve got me, you want to share me; if you share me, you haven’t kept me. What am I?

There is something which is always coming but never arrives?

What English word has three consecutive double letters?

I am the black child of a white father, a wingless bird, flying even to the clouds of heaven. I give birth to tears of mourning in pupils that meet me, even though there is no cause for grief, and at once on my birth, I am dissolved into air. What am I?