Which of the following conditions is characterized by increased cell numbers leading to tissue enlargement?

Hyperplasia is the condition characterized by an increase in the number of cells within a tissue or organ, leading to tissue enlargement. This process often occurs in response to a stimulus, such as hormonal changes, inflammation, or injury, and can be seen in various physiological and pathological conditions. In hyperplasia, the enlarged tissue retains its normal architecture, and this growth pattern can often be reversible once the stimulus is removed.

For example, during pregnancy, the uterus undergoes hyperplasia due to hormonal influences, increasing the number of uterine cells to accommodate the growing fetus. This differentiates hyperplasia from other conditions.

Hypertrophy, on the other hand, involves an increase in the size of existing cells rather than an increase in cell number, which does not lead to tissue enlargement through additional cell proliferation. Aplasia refers to the absence or failure of organ development, which results in a lack of cells, while hypoplasia indicates an underdevelopment or incomplete development of a tissue or organ, meaning there are fewer cells than normal.

Thus, hyperplasia is the most accurate choice among the given options for describing the condition of increased cell numbers that result in tissue enlargement.