Option A, B, D are only applicable for steroid hormones ( hydrophobic)
So the answer is C
Peptide bond joining the amino acid togather
Explanation:
A model is used to help scientists visualise things that they cannot actually see. It can be thought of as a thinking tool, to help form explanations. Models are useful simplifications to aid understanding. ... It can then be used to explain further phenomena and to make predictions of future behaviour.
<u>levels of organization </u>
from the smallest units of life to the largest units of the environment :
organelles >>> cells >>> tissues >>> organs >>> organ systems >>> organisms >>> populations >>> communities >>> ecosystems >>> biosphere
Experimental technique I believe