Answer:
approximately 4.5 billion years ago
Explanation:
Answer:
Explanation:
The four nitrogenous bases are A, T, C, and G. They stand for adenine, thymine, cytosine, and guanine. The four different bases pair together in a way known as complementary pairing. Adenine always pairs with thymine, and cytosine always pairs with guanine.
Answer:
Dermal tissue covers and protects the plant, and controls gas exchange and water absorption (in roots). Dermal tissue of the stems and leaves is covered by a waxy cuticle that prevents evaporative water loss.
Answer:
Mass extinctions happen because of climate change, asteroid impacts, massive volcanic eruptions or a combination of these causes. One famous mass extinction event is the one that lead to the extinction of dinosaurs, 65 million years ago.
Explanation: