How Does Temperature Affect The Growth Rate Of Seedlingss

Two experiments were performed to investigate the effects of temperature on the growth rate pine seedlings.
Experiment 1
A batch of 60 pine seedlings (Batch I) was grown in a greenhouse under controlled temperatures. Ten plants were grown at each of six temperatures from 50 C to 300 C. These plants remained at their original temperatures 24 hours each day for two weeks. All other conditions were the same for all seedlings. The growth rates are shown in Table 1.
Table 1. Growth rates for pine seedlings in Batch I

Experiment II
A second batch of 30 pine seedlings (Batch II) was kept at 250 C during the day (12 hours). However, during the night, three batches of 10 plants were moved to each of three different temperatures. All other
conditions remained the same as in experiment I. The growth rates are shown in Table 2.
Table 2. Growth rates for pine seedlings in Batch II

14. In experiment I, which is the best statement of the hypothesis that is being tested?

A. Temperature at which pine seedlings grow must remain constant from day to night.
B. The temperature at which pine seedlings grow must vary from day to night.
C. The optimal temperature for pine seedling growth is 250 C.
D.
The temperature at which pine seedlings are grown affects their growth rate.

15. Consider the following statement: When pine seedlings were grown at constant temperatures of either 250 C or 300 C, their growth rates were the same.

This statement is best described as:
A. Observation
B. Assumption
C. Theory
D. Hypothesis

16. The range of temperatures used in experiment I was probably chosen for which of the following reasons?
A. They represent temperatures at which pine seedlings can be grown.
B. They represent temperatures at which pine seedlings are known to grow rapidly.
C. They represent temperatures that have not been used in previous experiments.
D. They represent the only temperatures that can be controlled in a greenhouse.
17. Based on the information in the passage, which day and night temperatures resulted in the fastest growth of pine seedlings?
A. 250 C during both day and night
B. 300 C during both day and night
C. 250 C during the day an 200 C during the night
D. 300 C during the day and 250 C during the night
18. In table 1, temperatures of both 250 C and 300 C resulted in growth rates of 22.0 mm/day. Which of the following is the best interpretation of this result?
A. The maximum possible growth rate for pine seedlings is 22.0
mm/day.
B. The maximum possible temperature at which pine seedlings will grow is 300 C.
C. Under the conditions of experiment I, the growth rate of pine seedlings is greatest when theyare grown ate the same temperature all of the time.
D. Under the conditions of experiment I, growth rates of pine seedlings level off at 22.0 mm/day.

19. Based on the data in table 1, which of the following questions about experiment I CANNOT be answered?
A. How does growth rate vary from day to day during the two weeks of the experiment?
B. At which of the six experimental temperatures is the growth rate lowest?
C. How rapidly did the pine seedlings grow at 200 C?
D. What was the range of the average growth rate?

20. Which of the following is the best statement of the hypothesis being tested in experiment II?
A. Day temperature is a determining factor in the growth rate of pine seedlings.
B. Night temperature is a determining factor in the growth rate of pine seedlings.
C. The optimal temperature for pine seedling growth is 200C.
D. The maximum growth rate of pine seedlings occurs at night

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