Which physical attribute can be negatively influenced by undernutrition?

The correct answer is growth rate. Undernutrition can significantly affect a child's growth rate because it deprives the body of essential nutrients needed for proper development during critical growth periods. During early childhood, the body requires sufficient energy and nutrients to support rapid growth and development. When a child does not receive adequate nutrition, their growth rate can decline, leading to stunted growth and making it more challenging for them to reach their full genetic potential in height and weight later on.

While strength, weight, and height are also directly affected by nutritional status, growth rate is the most immediate and telling indicator of undernutrition. It reflects not just the nutrition level but also the body's ability to utilize that nutrition for proper development. Thus, slowed growth rate serves as a clear sign of undernutrition before other physical attributes become significantly impacted.