31 pairs
Spinal nerve, in vertebrates, any one of many paired peripheral nerves that arise from the spinal cord. In humans there are 31 pairs: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal. Each pair connects the spinal cord with a specific region of the body.
The lipid bilayer of biological membranes<span>, is intrinsically impermeable to </span>ions<span> and polar molecules. Permeability is conferred by two classes of membrane </span>proteins<span>, pumps and channels.</span>
Answer:
Genetic drift is referred to the changes in allele frequency in a gene pool. Gene flow is the process of alleles moving from one population to another.
Explanation:
The DNA is involved in both the process of inheriting traits and making proteins. It is a material that can be passed on to the next generation and determines the traits of an individual. When the protein is made, the cells can now express the trait or carry out the function.