Which of the following observations indicate that weight may be partially under genetic control?
I. Identical twin studies show similar body composition despite lifestyle differences.
II. Obesity rates have risen dramatically in recent decades with changes in food and lifestyle.
III. Children born of obese parents are much more likely to be overweight than the general population.

• A. I & II.
• B. I & III.
• C. II & III.
• D. I, II, & III.

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the question. The problem is asking which observations suggest that weight may be partially under genetic control. This involves identifying evidence that links genetics to body weight regulation.
2. Step 2: Analyze each observation. Observation I states that identical twin studies show similar body composition despite lifestyle differences. This supports the idea of genetic influence because identical twins share the same genetic makeup, and their similar body composition suggests a genetic component.
3. Step 3: Evaluate Observation II. It states that obesity rates have risen dramatically in recent decades with changes in food and lifestyle. This observation points to environmental factors (e.g., diet and lifestyle) rather than genetics, so it does not strongly support the idea of genetic control.
4. Step 4: Evaluate Observation III. It states that children born of obese parents are much more likely to be overweight than the general population. This supports the idea of genetic influence because children inherit genes from their parents, and this trend suggests a genetic predisposition to obesity.
5. Step 5: Combine the findings. Observations I and III provide evidence for genetic control of weight, while Observation II does not. Therefore, the correct answer is 'I & III.'