Why does lightning travel in a zig-zag manner rather than a straight line?

What is the humidity scale in reference to? Does 100% humidity mean the air has turned to water? Or is it 100% humidity when it is raining?

Why are some words, like "mama and papa", similar in many languages?

Why is chicken meat white, but beef red?

How did soldiers in hot countries in middle east and India survive the heat during wars wearing a metal body armor when temperatures in these regions touched 35 degree celcius (95f) in summer days?

My thought process is that using one eye would still cause enough uncomfortable sensations that closing / squinting both eyes is the only viable option but apparently not. One eye is completely normal and painless.This happened to me when I was driving...

There are infinite numbers between 0 and 1. There are also infinite numbers between 0 and 2. There would more numbers between 0 and 2. How can a set of infinite numbers be bigger than another infinite set?

How can a psychological factor like stress cause so many physical problems like heart diseases, high blood pressure, stomach pain and so on?