What would happen to the ecosystem when a keystone species, such as a wolf, is removed from the population entirely?

Which element is used in photosynthesis found in atmosphere and fixed by bacteria?

The oxidizing agent our bodies use to obtain energy from food is oxygen (from the air). if you breathe 15 times a minute (at rest), taking in and exhaling 0.5 l of air with each breath, what volume of air do you breathe each day? air is 21% oxygen by volume. what volume of oxygen do you breathe each day?

Which type of organism is missing from the food web seen in the illustration? primary consumers decomposers primary producers secondary consumers