Nerve cells are the longest. B
The correct answer is D. The genes are coded to produce specific proteins, by the process of transcription and translation.
These proteins then, lead to the production of characteristic traits like eye color, hair color etc.
So genes indirectly control the traits
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.