4. (a) Plant A was grown in soil with a low concentration of nitrates - Edexcel - GCSE Biology - Question 4 - 2012 - Paper 1

To calculate the mean leaf width for plant B, we first need to find the total width of the leaves measured. The widths for plant B are:

• 11.8 cm
• 10.3 cm

The total width is:

$ext{Total width} = 11.8 + 10.3 = 22.1 ext{ cm}$

Next, to find the mean, we divide the total width by the number of leaves:

ext{Mean width} = rac{22.1}{2} = 11.05 ext{ cm}

Thus, the mean leaf width for plant B is 11.05 cm.