Download App

Life Processes — Science STD 10 — Question

CBSE BoardEnglish MediumSTD 10ScienceLife Processes1 Mark
MCQ
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R)$. Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : The movement of water and dissolved salts in xylem is always upwards.
Reason : The upward movement of water is due to low pressure created by transpiration.
  • ✓
    Both $A$ and $R$ are true and $R$ is correct explanation of the assertion.
  • B
    Both $A$ and $R$ are true but $R$ is not the correct explanation of the assertion.
  • C
    $A$ is true but $R$ is false.
  • D
    $A$ is false but $R$ is true.
✓

Answer

Correct option: A.
Both $A$ and $R$ are true and $R$ is correct explanation of the assertion.
The plants take in water $($containing dissolved minerals$)$ from the soil through their roots. This water, called xylem sap is carried by the xylem vessels to all the parts of the plant. The xylem vessels of the root of the plant are connected to the xylem vessels of its stem. So, the water $($containing dissolved minerals$)$ enters from the root xylem vessels into stem xylem vessels. The xylem vessels of the stem branch into the leaves of plants. So, the water and minerals carried by the xylem vessels in the stem reach the leaves through branched xylem vessels. Since the cells of the leaf are losing water by transpiration, so water from the xylem vessels in the leaf will travel to the cells by osmosis to make up this loss of water. Thus, water is constantly being taken away from the top of the xylem vessels in the leaves thus reduces the effective pressure at the top of the xylem vessels. The pressure at the top of the xylem vessels $($in the leaves$)$ is lowered whereas the pressure at bottom of the xylem vessels remains high. Due to this water flows up the xylem vessels.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "Assertion - Reasoning (1 Marks)" from Life Processes→Life Processes — all question types→Science STD 10 question papers→CBSE Board STD 10 question papers→CBSE Board question paper generator→

Similar questions

Assertion (A): Ecology is study of relationship between living organisms and their environment.
Reason (R): The biotic community and non-living environment of an area function together to form an ecosystem.
→
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R)$. Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : Alkali metals do not form dipositive ions.
Reason : After loss of one electron, alkali metals achieve stable configuration of noble gas.
→
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R).$ Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : Higher the refractive index of the prism material, lower is the angle of deviation.
Reason : The angle of deviation is directly proportional to the angle of prism.
→
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R).$ Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below:
Assertion : The direction of force is given by Fleming's left $-$ hand rule.
Reason : A magnetic field exert a force on a moving charge in the same direction as the direction of field itself.
→
In the following questions, a statement of Assertion is given by the corresponding statement of Reason. Of the statements, mark the correct answer as :
Assertion : Solar cells are used to convert solar energy into electrical energy.
Reason : The radiant heat present in solar energy does not change into electrical energy.
→
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R)$. Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : The flow of energy in a food chain operating in an ecosystem is always unidirectional.
Reason : Lots of energy is lost as heat from living organisms at each trophic level of a food chain.
→
For two statements are given-one labelled Assertion $(A)$ and the other labelled Reason $(R)$. Select the correct answer to these questions from the codes $(a), (b), (c)$ and $(d)$ as given below:
Assertion: $\ce{2H_2S(g) + O_{2(g)} → 2S_{(g)} + 2H_2O_{(l)} }$lt is a redox reaction.
Reason: ln redox reaction, oxidation and reduction take place simultaneously.
→
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R).$ Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : Regeneration is getting a full organism back from its body parts.
Reason : Hydra and Planaria show regeneration.
→
Assertion (A): Recycling is the way of managing plastic waste.
Reason (R): Broken plastic articles are sent to plastic processing units where they are melted and remoulded to make new plastic articles.
→
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R).$ Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : Plastic, glass and metal wastes keep accumulating in our surrounding and their amount never reduces with time.
Reason : Plastic, glass and metal wastes are non $-$ biodegradable, and they cannot be decomposed by microorganisms.
→