Questions

Although  the image is inverted the mental interpretation of the effect on the retina is as though it is erect

In each segment of the circle, multiply the outer two numbers together and subtract the sum of the outer two numbers in the opposite segment to give the value in the  inner grey segment

The simplest form of matter that has a unique set of properties and is cannot be broken down into simpler substances by chemical means is called an Element.

An Atom is the simplest form of an element.

The simplest form of some elements is a Molecule. When an element consists of two identical atoms it is called a diatomic molecule.

A substance that contains two or more elements chemically combined in a fixed proportion is called a Compound.