Answer:b
Explanation:I believe it’s b I looked it up on google
Answer:
Savanna do not exist in the united states because there are no true tropic climates.
Answer:
Lymphatic: bacteria invade the body but are removed with the help of cells
Endocrine: A chemical message is signaled to help the body relax and sleep
Nervous: The brain signals for the muscles to contract
Explanation:
Lymphatic system is the part in the body that uses the cells in your body to help it.
The endocrine system is about hormones and how the body needs to maintain stable and have homeostasis.
The brain is part of the nervous system and it sends signals to other parts of the body.
20.4 21.3 are the correct answers
Organisms are the biotic parts of an ecosystem.
