What is an example of continuous variation?
A) ABO blood groups in humans
B) body mass in humans
C) seed shape in pea plants
D) seed colour in pea plants
▶️ Answer/Explanation
Ans: B
Continuous variation shows a range of intermediate values between two extremes, influenced by multiple genes and environmental factors.
- Body mass in humans (B) is continuous because it can vary across a wide range (e.g., 40 kg to 120 kg) with many possible intermediate values.
- The other options (A, C, D) are examples of discontinuous variation (distinct categories with no intermediates).
Thus, the correct answer is B (body mass in humans).
The graph shows the percentage of a population with different phenotypes for the same characteristic.
Which characteristic in humans is represented by X?
A) ABO blood groups
B) arm length
C) height
D) mass
▶️ Answer/Explanation
Ans: A
The graph shows discrete categories (distinct bars), which is characteristic of ABO blood groups (A, B, AB, O). These are determined by specific alleles and show no intermediate values.
Options B, C, and D (arm length, height, mass) are continuous traits that would display a smooth bell curve, not separate bars. Thus, A is the correct answer.