This is the exact answer:
Bacteria are helpful because they produce oxygen, which our bodies need to breathe, and they help us to digest the food we eat. Bacteria are also helpful because they are used in medicine to help us overcome disease. Bacteria are harmful because they can cause tooth decay and illnesses that can be either common or quite serious.
Answer: Primary succession occurs after a volcanic eruption or earthquake; it involves the breakdown of rocks by lichens to create new, nutrient -rich soils. The first species to colonize an area after a major disturbance are called pioneer species; they help to form the new environment.
Explanation:you welcome
Answer:
A biome is a group of ecosystems with the same climate
Explanation:
Answer: corpus luteum secretion
Explanation: