Critical Reasoning – Early childhood development: "Lack of stimulation in the first four or five years of life can have adverse consequences." Identify which assumption(s) are implicit: (I) A large part of observed intelligence develops in the earliest years of life; (II) About 50% of measurable intelligence at 17 is already predictable by age four.

Given data

• Claim: Low stimulation in ages 0–5 → adverse consequences.
• Assumption I: Early years are critical for intelligence development.
• Assumption II: A precise quantitative claim (50% at 17 predictable by age 4).

Concept/Approach
To justify the strong emphasis on early stimulation, one must accept the qualitative importance of early development (I). A specific numeric threshold (II) is not required for the claim to stand.

Step-by-step reasoning
• If early years were not critical, lack of stimulation would not be strongly consequential → I must hold.• The statement does not rely on an exact percentage; any substantial early impact suffices → II is not necessary.

Verification/Alternative
Deny I → undermines the causal link. Deny II → the qualitative claim remains fully intact.

Common pitfalls

• Assuming a qualitative claim commits to a specific quantitative metric.

Final Answer
Only assumption I is implicit.