2.1 Grade 11 leamers wanted to investigate the growth of bacteria on culture plates

The culture plates contained different nutrients as shown in the table below.

Culture plate number

1

2

Nutrient A

Nutrient B

Nutrient C

7

7

✓

✓

7

✓

They used a sterile needle to place the bacteria on each plate. After a few days

they counted the number of colonies on each culture plate. The results are

shown in the table below.

Culture plate number

Number of bacterial colonies

10

2

50

3

9

2

2.1.1 Formulate a hypothesis for the investigation.

2.1.2 Identify the dependent variable for this investigation.

2.1.3 In which plate were the most colonies found?

2.1.4 Suggest a reason why most colonies were found in the plate mentioned

In your answer in QUESTION 2.1.4.

2.1.5 According to these results, which is the most important nutrient for

bacterial growth?

2.1.6 Mention TWO factors that learners should keep constant during the

investigation

2.1.7 State TWO ways in which the leamers could increase the reliability of the

investigation.

2.1.8 Draw a bar-graph to show the leamers' results.

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