In order to become a herbalist, you need to have a basic understanding of herbs. Also, you need to train to be a herbalist(go to college, university,etc.). You can start learning about plants/medicine.
The circulatory system, if I am not mistaken!
Hope this helped!
I believe A because you can find a way no matter of the environment
Depend on what you mean by what kind of competition, if you talk about competition for food, some bird population may be getting smaller and have a hard time to reproduce because they can't get enough food for themselves.
Answer:
One study found that self-esteem had differing effects on sexual behaviors in teen boys and girls: Younger girls with lower self-esteem are more likely to engage in sexual activity. ... Boys who have high self-esteem are nearly 2.5 times more likely to initiate sex