Cells are the basic building blocks of tissues. All cells experience changes with aging. They become larger and are less able to divide and multiply. Among other changes, there is an increase in pigments and fatty substances<span> inside the cell (lipids).</span>
The proteins are the main building blocks for the tissues and the organs and as they help the cells to grow and replenishment and repair of the tissue depends on them. They are thus used as a daily source of the dietary energy, and they s<u>erve as the basic unit of the function in the body </u>and are known as the extracellular matrix.
First eliminate choices C and D since they both mention that fact 1 is crossing over ( which is also referred to as genetic recombination) . So you're left with A and B and the correct answer is B .
