**Core Concept**
The water content in infants is crucial for their growth and development. At birth, infants have a high water content, which gradually decreases as they mature. This water content is distributed between intracellular and extracellular compartments, playing a vital role in maintaining proper bodily functions.

**Why the Correct Answer is Right**
Infants have a high water content, approximately 70-80% of their body weight, which is significantly higher than adults. This high water content is due to the abundance of water in their tissues, including the brain, muscles, and blood. As infants grow and mature, their water content gradually decreases to approximately 50-60% of their body weight by adulthood. This decrease in water content is due to the changes in tissue composition and the development of more efficient water conservation mechanisms.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not provide a specific percentage of water content in infants.
**Option B:** This option is incorrect as it implies that infants have the same water content as adults, which is not true.
**Option C:** This option is incorrect as it suggests a high water content of 90%, which is an overestimation.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the high water content in infants makes them more susceptible to dehydration due to their limited ability to conserve water. This is a crucial consideration in pediatric care, especially in cases of diarrhea or vomiting.

**Correct Answer: C. 70-80%**