Glassy igneous rocks (i.e. obsidian) are cooled very rapidly.
I drinked eight cups a day
What causes alteration of plant debris that make coal?
fine debris emitted as a byproduct of coal combustion. coal, oil, or natural gas. Fossil fuels formed from the remains of ancient plants and animals. device used for heating by burning a fuel, such as wood or coal.
Mature ovum is being produced in oogenesis, while spermatogenesis has four mature sperms that contains enzymes due to that the sperm is able to penetrate an egg
