Download App

Human Health and Disease — BIOLOGY STD 12 Science — Question

Maharashtra BoardEnglish MediumSTD 12 ScienceBIOLOGYHuman Health and Disease1 Mark
MCQ
For question, two statements are given$-$one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes $(a), (b), (c)$ and $(d)$ as given below.
Assertion : Dendritic cells originate in the bone marrow.
Reason: Dendritic cells are found in neuron.
  • A
    Both assertion and reason are true, and reason is the correct explanation of assertion.
  • B
    Both assertion and reason are true, but reason is not the correct explanation of assertion.
  • ✓
    Assertion is true, but reason is false.
  • D
    Both assertion and reason are false.
✓

Answer

Correct option: C.
Assertion is true, but reason is false.
Dendritic cells are immune cells and form part of the immune system. They are present in those tissues which are in contact with the environment; in the skin $($where they are often called Langerhans cells$)$ and the lining of nose, lungs, stomach and intestines. They have long spiky arms, called dendrites, hence the name. $($Neurons also have dendrites, but dendritic cells have nothing to do with neurons$)$.

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 (A) & Reason (B) MCQ" from Human Health and Disease→Human Health and Disease — all question types→BIOLOGY STD 12 Science question papers→Maharashtra Board STD 12 Science question papers→Maharashtra Board question paper generator→

Similar questions

Two statements are given $-$ one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes $(a), (b), (c)$ and $(d)$ as given below.
Assertion : Both the passenger and vehicle $\text{DNAs}$ are treated separately with separate restriction endonuclease.
Reason : Ligation is done by the use of alkaline phosphatase and $\text{DNA}$ ligase.
→
For two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes $(a), (b), (c)$ and $(d)$ as given below.
Assertion: Chasmogamous flowers require pollinating agents.
Reason: Cleistogamous flowers do not expose their sex organs.
→
For question two statements are given $-$ one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes $(a), (b), (c)$ and $(d)$ as given below.
Assertion : Ectotherms are able to remain active under cold conditions.
Reason : Ectotherms are able to maintain a constant internal temperature, even when the temperature outside fluctuates.
→
Read the following and answer any four questions from $(i)$ to $(v)$ given below:
The anther is a four$-$sided structure consisting of four microsporangia located at the corners, two in each lobe. $TI1e$ microsporangia develop further and become pollen sacs. In a transverse section, a typical microsporangium appears near circular in outline. It is generally surrounded by four wall layers$-$the epidermis, endothecium, middle layers and the tapetum.
  1. A dithecous another consists of $(A)$ microsporangia, $(B)$ in each lobe.
Select the option that correctly fills the blanks.
S. No
 $A$ $B$
$(a)$
Four
Two
$(b)$
Two
One
$(c)$
Two
Two
$(d)$
Four
One
  1. The given diagram shows microsporangium of a mature anther. Identify $A, B$ and $C.$
$(a)$
$A-$Middle layer
$B-$Endothecium
$C-$Tapetum
$(b)$
$A-$Endothecium
$B-$Tapetum
$C-$ Middle layer
$(c)$
$A-$Endothecium
$B-$Middle layer
$C-$Tapetum
$(d)$
$A-$Tapetum
$B-$Middle layer
$C-$Endothecium
  1. The function of labelled part $X$ is:
  1. Dehiscence.
  2. Mechanical.
  3. Nutrition.
  4. Protection.
  1. Select the incorrect statement.
  1. Microsporangium is generally surrounded by four wall layers$-$epidermis, endothecium, middle layers and tapetum.
  2. Outer three layers perform functions of protection and dehiscence of anthers.
  3. Cells of tapetum possess dense cytoplasm and generally have more than one nucleus.
  4. Cells of tapetum undergo meiosis and produce microspore tetrads.
  1. Which function oftapetum is correct?
  1. Helps in pollen wall formation.
  2. Transportation of nutrients to inner side of another.
  3. Synthesis of callase enzyme for separation of microspore tetrads.
  4. All of these.
→
Two statements are given $-$ one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes $(a), (b), (c)$ and $(d)$ as given below.
Assertion : Restriction endonuclease recognises palindromic sequence in $\text{DNA}$A and cuts them.
Reason : Palindromic sequence has two unique recognition sites Pst $I$ and Pvu $I$ recognised by restriction endonuclease.
→
For question two statements are given $-$ one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes $(a), (b), (c)$ and $(d)$ as given below.
Assertion : Alpha diversity is said to be higher if the dissimilarity between communities is higher.
Reason : Alpha diversity is a measure of diversity between the communities.
→
For question two statements are given $-$ one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes $(a), (b), (c)$ and $(d)$ as given below.
Assertion : Communities with more species tend to be more stable than those with less species.
Reason : Conununities with more species is not able to resist occasional disturbances.
→
For question two statements are given$-$one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes $(a), (b), (c)$ and $(d)$ as given below.
Assertion: Mendel was successful in his hybridisation experiments.
Reason: Garden pea proved to be an ideal experimental material.
→
For question, two statements are given$-$one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes $(a), (b), (c)$ and $(d)$ as given below.
Assertion : Cancer patients are given chemotherapeutic treatments.
Reason: Chemotherapeutic agents are used to destroy malignant cells.
→
For question, two statements are given$-$one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes $(a), (b), (c)$ and $(d)$ as given below.
Assertion : $\text{SCID}$ is the first genetic disorder to be combated with gene therapy.
Reason : $\text{SCID}$ is a type of allergy.
→