The ideal way to study the property of different types of neurons is to control individual types of cells independently and see what happens when you alter one type of cell. Optogenetics helps to realize this goal.

Brain cells are normally not sensitive to light. So by introducing light-sensitive proteins into specific types of neurons, we can now selectively control that specific type of neuron by shining light in the brain.

Basically, when you look at different types of cells, such as fibroblasts, which form connective tissue, or epithelial cells, from saliva, you see general correlations within a person. If telomeres are up for one cell type, they're up for others overall.

There are over 7,000 different types of proteins in typical eukaryotic cells; the total number depends on the cell class and function.

My go-to prebikini flat-ab move is the plank, all different types.

Different times need different types of leadership.