Which of the following are noticeable characteristics of a 9-month-old infant?

At nine months of age, infants typically exhibit a range of developmental milestones. One key characteristic is their tendency to explore their environment using their senses, which includes placing objects in their mouth as a way to learn about them. This behavior is a natural part of their development as they seek to understand the world around them.

Additionally, many nine-month-old infants begin to demonstrate gross motor skills such as pulling themselves up to a standing position. This action signifies not only their improving strength and coordination but also their growing independence as they prepare for walking.

In contrast, the other options describe milestones that are either too advanced for a nine-month-old or do not accurately reflect the typical behavior of infants at this age. Understanding these developmental characteristics is essential for recognizing typical growth patterns in infants, which can assist caregivers and healthcare providers in monitoring and supporting healthy development.