## **Core Concept**
Gerontology is the multidisciplinary study of the aging process, focusing on the physical, psychological, and social aspects of aging. It encompasses the examination of age-related changes, health issues, and societal implications associated with aging. The field aims to understand and address the challenges faced by older adults.

## **Why the Correct Answer is Right**
The correct answer, **D. Aging and aged**, directly corresponds to the definition of gerontology. Gerontology involves the study of aging processes and the challenges faced by the aged population. This includes understanding biological aging, psychological changes, and social factors influencing the elderly.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because it does not specify what "growth and development" refer to, making it too vague for the precise definition of gerontology.
- **Option B:** This option is incorrect as it relates more to the study of children (pedology or pediatrics) than to the study of aging or the aged.
- **Option C:** This option is incorrect because embryology is the study of embryo development, which is unrelated to gerontology.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that while gerontology is the study of aging, geriatrics is the branch of medicine focused on the health care of elderly people. Understanding the distinction between these two fields can help in identifying the correct application of each term in medical and social sciences.

## **Correct Answer:** D. Aging and aged