Nitrogen Fixating bacteria ( such as cyanobacteria or clostridum) can convert gaseous nitrogen in the air into amonia, a compound that organism can use to make amino acid and other nitrogen-containing organic molecules
A constant is something that is kept the same throughout the course of a experiment. So I would guess C) because they are not doing anything special. If it’s not C then it is A. :)
Answer:
I think that birds have different bill lengths because of their habitats and their diet. Also natural selection and evolution has also played a factor due to the fact that birds have not always looked the way that they do now, for example the Archaeopteryx a bird that lived around the time of the dinosaurs had a shorter and more powerful bill to grind insects and small mammals
Explanation:
Because neurones will not function properly neither will neuroreceptors if a person lacks neurotransmitters, these two parts (transmiters and receptors) all work together and depend on eachother.
Neurones are resposible for transmitting informations trought the body, and if neurotransmitters are no-existent, information may not be able to get to some body parts since neurotransmitters transmit the information.
Hope it helped,
Happy homework/ study/ exam!