c. It never changes during the experiment.
Answer:
A scientific law is simply an observation of the phenomenon that the theory attempts to explain. For example, suppose that you were lying under an apple tree and observed an apple fall from a branch to the ground. The observation of this phenomena can be called the law of gravity.
Cnidarians were the first phylum that scientists saw tissue level organization in. Tissue level organization meaning cells all of one type start to function in a unified way.
The similarity in the arrangement and structure exists mostly with the quads because we, just like cats, need to be able to flex and extend them so we need a lot of strength in them.
Amino acids are the building blocks that make up proteins.