1. How many layers are there in Earth’s atmosphere?
- 5
- 3
- 7
- 1
1
7. Oxygen liberated during photosynthesis is coming from?
- Water
- Air
- Fire
- Soil
25
9. Which structure of the eye is the most sensitive but contains no blood vessels?
- Cornea
- Iris
- Pupil
- Lens
33