Which type of pathogen causes diseases like chickenpox and rabies, and cannot be cured? a. bacteria b. fungi c. protozoans d. viruses

D. viruses ( why does it have to be 20 characters)

Cognitive development is the first period of infant called Piaget. During the sensorimotor stage, the child task is to use their sense and skills to understand the thing around them and explore what the world has.  Infants reach the stages of Piaget’s sensorimotor intelligence earlier than the Piaget prediction.