Number of teeth present in the oral cavity at the age between 8-9 years:
**Core Concept**
The development and eruption of teeth in the human oral cavity follows a specific timeline. At birth, the oral cavity is edentulous, and teeth begin to erupt at around 6 months of age. By the age of 8-9 years, the oral cavity contains a mix of primary and permanent teeth.
**Why the Correct Answer is Right**
Between the ages of 8-9 years, most children have a combination of primary and permanent teeth. The first permanent molars typically erupt around the age of 6 years, followed by the central incisors. At this stage, the child has 24 primary teeth being replaced by 32 permanent teeth, but not all are erupted.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it likely represents the number of teeth present at a younger age.
**Option B:** This option is also incorrect as it may correspond to an earlier stage of tooth development.
**Option D:** This option is incorrect as it might represent the total number of permanent teeth that will eventually be present.
**Clinical Pearl / High-Yield Fact**
It is essential to remember that the eruption of teeth can vary among individuals, but generally, by age 8-9, children have a mix of 24 primary and some permanent teeth, totaling around 24-28 teeth.
**Correct Answer:** C. 24