Some students want to determine if the colour of light affects plant growth - HSC - SSCE Biology - Question 8 - 2008 - Paper 1

To determine if the colour of light affects plant growth, we need to formulate a hypothesis that can be tested through experimentation. A suitable hypothesis should be specific and measurable, allowing for a clear comparison.

Among the options:

• Option (A) states that all plants will grow better in red light, but it is too general and does not allow for comparison between different light colors.
• Option (B) suggests that all plants will grow bigger flowers in sunlight, which again is too broad.
• Option (C) specifies that pea plants will grow taller in red light than in blue light, allowing for measurable comparison between two specific conditions.
• Option (D) states that pea plants will grow faster than bean plants in coloured light, which is a comparative statement but does not focus on light color specifically affecting the growth of the same type of plant.

Therefore, the best hypothesis to be tested is (C) since it focuses on a specific comparison between the growth of pea plants under different light conditions, making it a suitable hypothesis for scientific investigation.