Definition

• Layer of gases

• Surrounds Earth

• Held by gravity

Composition

• Nitrogen – 78%

1.Autotrophic

• Make their own food

• eg-cyano bacteria,some algae

2.Hetrotrophic

• Cannot make their own food

a.saprophytus

Questions

🦠 Microorganisms – Mystery & Wonder Questions

1. If bacteria are too small to see, how do they "talk" to each other?

2. Why would tiny bacteria need to communicate before doing something together?

3. How can millions of tiny microorganisms make an entire beach glow at night?

4. If your body contains trillions of microbes, why don't they all make you sick?