The majority of signal molecules are peptides and small proteins. Both are made of a chain of amino acids, the difference being the number of amino acids that make up the molecule. Generally, if the signal molecules has fewer than 50 amino acids it is considered a peptide. If it has more it is considered a protein.
Explanation:
Many factors can affect the rate of diffusion , including , but not limited to , concentration gradient , size of the particles that are diffusing , and temperature of the systems , diffusion of substances in and out of cells is mediated by the plasma membrane .
I believe that present day was a theory that became a evolution developed because it was a historical event involved
Answer and explanation;
The level of organization in human body is;
cells → tissues → organs → organ systems → the organism.
-Cells are the smallest unit of any living thing. it is the basic unit of living organisms.
-Tissues are groups of specialized cells working together to perform a specific function.
-An organ is a complex system of tissues working together to perform a life task for a human body. Examples: Heart, lungs, liver, kidneys, eyes, brain, stomach, intestines, and pancreas are a few of the organs that reside in the human body.
-An organ system is a group of organs working together to keep the human body alive. They include; Digestive system, Respiratory system, Endocrine system, Immune system, etc.
