Question

Four-month-old michaela groups stimuli on the basis of shape and size. this means that michaela is able to __________.

Answer 1

I believe the answer is: Categorize

Categorizing refers to the process of assigning specific objects or subjects to several groups based on their similarties. (such as based on size and shapes)
On average,Children's cognitive ability to make categorisation started to develop by the age of 4-13 months