In piaget's theory, the stage of development between birth and 2 years of age, in which the individual uses senses and motor abilities to interact with objects in the environment, is called the stage.
a. concrete operations
b. sensorimotor
c. preoperational
d. formal operations
e. schematic

Sensorimotor stage

Explanation:

The sensory-motor stage is the first stage out of four stages given by Piaget's theory of cognitive development. It starts from birth to 2 years. It is the periods of rapid growth. the child learns through his senses and actions. The child use assimilation and accommodation process to adapt to the world.  

This stage is broken in six sub-stages:

Object permanence, the object concepts which is related to the existing and event occurs in the world independently of self actions

the median of the data is 4.

step-by-step explanation:

the median means the middle number of a given number.

to decide which one is the median, arrange in ascending or descending order. but sometimes, you may find two(2) number in the middle, but it's easy, just add them together and divide by 2.

so,   determine the median of the data. 2, 3, 3, 4, 5, 7, 9

it is already arranged, count 3 times forward and 3 backward and the one left is your answer.

2,3,3,4,5,7,9

our answer is 4.

hope this !