Why is thyroxin essential in humans ?

Why is friction essential ?

Why is it essential to wash the precipitate with water before estimating it quantitatively?

What is the scientific name of human beigns?

Explain Essential amino acids.

Explain why (a) The blood pressure in humans is greater at the feet than at the brain

Name one lectin and one essential oil in plants.

What is interference of light? Write two essential conditions for sustained interference pattern to be produced on the screen. Why interference pattern is not detected when two coherent sources are far apart?