What conditions are typcial of the soil the deeper we dig into it?

What did the first language sound like

What are examples of the plant life and animal life that can be found in each type of terrarium

Males of different species of the fruit fly drosophila that live in the same parts of the hawaiian islands have different elaborate courtship rituals. these rituals involve fighting other males and making stylized movements that attract females. what type of reproductive isolation does this represent?