Final answer:
Max is likely a toddler around 12-24 months old, displaying separation anxiety, a common stage of development where children experience distress when separated from caregivers.
Step-by-step explanation:
Max, who cries and clings to his mother when she leaves for day care, is likely experiencing separation anxiety, which is common in toddlers.
This behavior is typical for children around 12-24 months old, a time when they begin to understand object permanence and develop strong attachments to their caregivers. It's a phase where children are still learning to cope with the absence of parents or primary caregivers, expressing distress in their absence as seen with Max's behavior.