Air is a mixture of different gases.
Nitrogen – 78%
Oxygen – 21%
Other gases – 1%
(noble gases etc…)
Air is a mixture of different gases.
Nitrogen – 78%
Oxygen – 21%
Other gases – 1%
(noble gases etc…)

There are two coordination systems in humans The nervous system 2. The endocrine system

What are ions? How are ions formed? Positive ions – cations Negative ions – anions

Blood and its components Red blood cells White blood cells Platelets Plasma

Scientific method has the following steps: Observation Hypothesis Experiment Theory Conclusion

Using Resources: Life cycle assessment & Recycling Ways of reducing the use of resources Advantages of Recycling