The nitrogenous bases cytosine and thymine are pyrimidine
DNA is formed by purine bases (adenine and guanine) which have the fundamental structure of the purine heterocycle and by pyrimidines (cytosine and thymine) which are derived from the pyrimidine ring.
the correct answer is option b
behavioral response need communication and thus co-ordination at several levels such as interaction among cells, organ system and the entire organism.
behavioral response produces both internal and environmental stimulus.
answer: collecting information/data
reason: the student is going around and asking people questions to collect data
i hope this