Questions

This is a layer of atmosphere about 60 to 70 km above the earth and extends to about 400km. It contains ionised particles which can reflect radio waves making radio communication round the world possible.

The Aufbau Principle states that in the ground state of an atom, an electron enters the orbital with lowest energy first and subsequent electrons are fed in the order of increasing energies.

Nutrients are the substances in food that provide the raw materials and energy the body needs to carry out all its essential processes.

There are six groups of nutrients:

1. Carbohydrates.

2. Fats.

3. Proteins.

4. Vitamins.

5. Minerals.

6. Water.