Um I think it's 3 but I might be incorrect
I am afraid there is no specific answer to your question becuase there is not only one fell good chemical, there are 4:
Endorphin, Serotonin, Oxytocin and Dopamine.
Hope it helped,
Happy homework/ study/ exam!
In biology, evolution is the change in the characteristics of a species over several generations and relies on the process of natural selection. The theory of evolution is based on the idea that all species? are related and gradually change over time.
Answer:
The correct answer is They are very common in symbiosis in all plant families.
Explanation:
Nitrigen fixation is a process in which the atmospheric nitrogen is converted to ammonia by the help of nitrogen fixing bacteria such as azobacter, clostridium.
These bacteria lives in the root nodules of leguminous plants and some of them are free living soil bacteria such as azobacter.
These bacteria only form symbiotic relationship with the root leguminous plants but not with other plant families.
What you need help with maybe i can help??
