What occurs twice in a week, once in a year but never in a day?

In the figure, you can see nine stars. What you have to do is connect all of them by using just four line and without lifting your hand i.e. in a continuous flow.

It is a nine-letter word.
The exact opposite of the phrase "friendly and outgoing"
It contains the word "over".
It starts will a vowel.

What is it?

What can run but never walks, has a mouth but never talks, has a head but never weeps, has a bed but never sleeps?

What three numbers, none of which is zero, give the same result whether they’re added or multiplied?

What seven-letter word has hundreds of letters in it?

Which word does the below Plexor means ?

A Scientist was fifty years old in the year 2000 but he was forty years old in the year 2010. How can this be possible?

PS: It has a logical answer.

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

O_er_t_o_

Complete the missing letters of the given word.