Which of the following gross motor skills is expected by age 4?

The skill expected by age 4 is that children can skip and hop on one foot. This milestone indicates a level of coordination and balance that is typical for this age group. By age 4, children are developing their gross motor skills and are able to perform movements that require more control and stability. Skipping and hopping are activities that involve alternating movements and using one foot effectively, showcasing their progress in physical development and coordination.

Riding a tricycle is often expected slightly earlier, around age 3. Throwing a ball overhead typically develops around ages 3 to 4, but it is not as advanced in terms of balance and coordination as skipping or hopping. Jumping off a bottom step can also be seen at this age, but it does not reflect the same complex skill set involved in skipping and hopping.