During what stage do you learn abstract thinking skills

The finches on the galapagos island were similar in form except for variations of their beaks. darwin observed that these variations were useful for: attracting a mate defending territory building nests gathering food

When you run, you begin to breathe heavier and faster. your heart beats more quickly, bringing more oxygen to your cells. which organ systems are working together here?

When lactate builds up in a runners muscles it causes a burning sensation what causes this to occur