Question

Yousef measured the height of each seedling on day 1 and day 7. These are his results.

Group
Seedling
Increase in
height/mm
A no water
6.5
0.5
0.5
0.5
5.5
B 2 cm water
Height of seedling/mm
Day 1
Day 7
- 6.0
5.5
6.0
6.0
5.5
7.5
6.0
8.0
6.0
8.5
6.0
9.5
5.5
9.5
6.0
10.0
2.0
00 UN
2.0
2.5
C5cm water
a
b
C
Calculate the increase in height for each of the seedlings 7, 8 and 9.
Calculate the mean increase in height for each group of seedlings.
On graph paper, draw a bar chart to show Yousef's results. Put volume of
water on the x-axis, and mean increase in height on the s-axis.
Write a conclusion that Yousef could make from his results.
d
1 Plants

Answer 1

The main difference causing variation in mean stem length between the plants from the two dishes is the presence or absence of light, which affects photosynthesis and plant growth.

Step-by-step explanation:

The most probable cause for the difference in mean stem length between plants in dish A (no light) and dish B (light cycle) is the effect of light on plant growth. Plants in dish A, with no exposure to light, likely did not undergo photosynthesis effectively, resulting in shorter stems. On the other hand, the plants in dish B received a 14-hour light cycle, allowing them to photosynthesize and grow taller.

In terms of experimental variables, the key difference between the groups is the presence of light, a critical factor for photosynthesis, and consequently, plant growth. This is supported by the fact that other conditions were kept consistent for both dishes.