case /data -based (4 Marks)

Question 14 Marks

The picture shows the nitrogen cycle.

$9.$ How do plants take up nitrogen$?$
$A.$ She should repeat the same experiment.
$B.$ She should leave the test tube undisturbed for six hours.
$C.$ She should repeat the experiment with test tubes containing more sugar solution.
$D.$ She should keep an extra set of test tubes with sugar solution but without the yeast.
$10.$ Plants and animals are continuously using nitrogen. Will there be a depletion of nitrogen in the environment due to this continuous use$?$ Explain your answer.

Answer

$9. C.$ From nitrogenous compounds in the soil
$10.$ Mentions that nitrogen in the environment will not get depleted because
it is recycled and reused in the environment.

View full question & answer→

Question 24 Marks

Manoj adds some yeast to two test tubes containing sugar solution.
One test tube is kept in ice and the other at room temperature.
The picture shows what happens after three hours.

$5.$ What is Manoj investigating$?$
$A.$ Does yeast grow in sugar solution only$?$
$B.$ Does yeast convert sugar into alcohol$?$
$C.$ Does temperature affect the growth of yeast$?$
$D.$ Which gas is produced as yeast grows in sugar solution$?$
$6.$ How can Manoj conirm if the gas produced in the test tube at room temperature was due to the yeast growing in it$?$
$A.$ She should repeat the same experiment.
$B.$ She should leave the test tube undisturbed for six hours.
$C.$ She should repeat the experiment with test tubes containing more sugar solution.
$D.$ She should keep an extra set of test tubes with sugar solution but without the yeast.
$7.$ What should Manoj keep the same in both the test tubes for a fair experiment$?$
Circle ‘Yes’ or ‘No’ for each row.

Should this be kept same for both the test tubes?	Yes or No
The concentration of sugar solution	Yes/No
The colour of the balloons	Yes/No
The amount of yeast added to each test tube	Yes/No

$8.$ What type of organism is yeast$?$
$A.$ Fungi
$B.$ Algae
$C.$ Bacteria
$D.$ Protozoa

Answer

$5. C.$ Does temperature affect the growth of yeast$?$
$6. D.$ She should keep an extra set of test tubes with sugar solution but
without the yeast.
$7.$ Yes
No
Yes
$8. A.$ Fungi

View full question & answer→

Question 34 Marks

Suman wants to see how quickly carrots lose colour. Loss of colour shows rotting of carrot.
She observes carrot slices on a plate under three different conditions as shown below.

She notes how long the carrot slices on each plate take to change colour.

	Under the sun	In a moist room at $25^\circ C$	In the refrigerator
Time carrot slices take to change colour	$2$ days	$5$ days	$8$ days

$3.$ What can Suman conclude from her activity$?$
$A.$ Carrots when kept under the sun do not rot easily.
$B.$ Carrots at room temperature lose colour more quickly.
$C.$ Carrots can be best preserved in hot and moist conditions.
$D.$ Carrots take more time to lose colour under cold conditions.
$4.$ Use the results of the activity to inish the graph below. The irst bar is drawn for you.
Put a label in the space provided for the axis on the left.

Answer

$3. D.$ Carrots take more time to lose colour under cold conditions.
$4.$ Answers both parts of the question correctly.
● Shades the two bars on the graph correctly and
● Labels the Y-axis correctly, for example, time taken to lose colour (in days)/days taken to lose colour.

View full question & answer→

Question 44 Marks

A trash can contains the following materials.
• Plastic straw
• Aluminium foil
• Tissue paper
• Glass bottles
• Chicken bones

$1.$ Select the materials from the list that can be decomposed by microbes?
$2.$ Rohit is suffering from stomach ache and is passing watery stool. What should Rohit do to prevent the spread of infection to other family members?
$A.$ He should eat properly cooked food.
$B.$ He should wear a mask all the time.
$C.$ He should maintain distance from other family members.
$D.$ He should wash his hands with soap after using the bathroom.

Answer

$1.$ Identiies the two materials that can be decomposed by microbes.
● Chicken bones
● Tissue paper
$2. D.$ He should wash his hands with soap after using the bathroom.

View full question & answer→

Science case /data -based (4 Marks)

Test yourself on this topic