Name the three-letter word that can complete the below words?

A) L O _ _ _ E
B) E D U _ _ _ E
C) _ _ _ E R
D) _ _ _ T L E

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?

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

Railroad Crossing, look out for the cars. Can you spell that, without any R's ?

What goes up but never comes down?

By using 'because' continuously three times, can you make an English statement ?

A plane crashed between the border of Mexico and America. Where do you bury the survivors?

I taste better than I can smell. Who am I?

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