What 4-letter word can be written forward, backward or upside down, and can still be read from left to right?

Can you solve the tricky chess rebus puzzle below by ciphering the hidden meaning?

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

What runs around the whole yard without moving?

It has a long neck, A name of a bird, Feeds on cargo of ships, It's not alive,

What is it?

Let's play a word game. Following are some meaningless words that can be completed by adding random letters on either side of the word.

For example, the word "rdo" can be formed into "pardon".

Using the same technique, can you complete the given words?
ecalc
airb
rinci
tibac
uidel
gorit
igna
eyho

A patient was diagnosed with some ailment. He was given five different tablets to take at night at an interval of 15 minutes.

How long will it take the patient to consume all the five tablets?

If a boy blows 18 bubbles,
Then pops 6 eats 7 and then
He pops 5 and blows 1.
How many are left?

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

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?