On because of the suns heat. So, it would be on to protect it from sunburn.
Answer:
4.5 billion years ago
Earth hasn't always been a blue and green oasis of life in an otherwise inhospitable solar system. During our planet's first 50 million years, around 4.5 billion years ago, its surface was a hellscape of magma oceans, bubbling and belching with heat from Earth's interior.
Explanation:
Answer: ONLY CERTAIN SUBSTANCES CAN PASS THROUGH IT
Explanation:
1 only gases and water can pass through it.
2 substances need permission to pass through it.
3 only certain substances can pass through it.
4 substances need carrier molecules to pass through it.
5 ATP is always needed to move molecules across the plasma membrane.
