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 : Inflammatory response is produced in the body after some infections.
Reason: This is one type of defence mechanism.
  • ✓
    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.
  • C
    Assertion is true but reason is false.
  • D
    Both assertion and reason are false.
✓

Answer

Correct option: A.
Both assertion and reason are true and reason is the correct explanation of assertion.
Infection or tissue injury often results in redness and swelling, along with pain and production of heat that may result in fever. Such manifestation is localized and, is known as inflammatory response. This response occurs due to release of chemical signals, alarm signals, notably histamine and prostaglandins,by the damaged mast cells. There is a leakage of vascular fluid, which contains serum proteins with antibacterial activity. Further, there is an influx of phagocytic cells into the affected area. These responses inhibit and destroy the invading microorganisms. Thus, inflammatory response is said to be a defence mechanism.

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

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.
→
Silencing of a gene could be achieved through the use of :
→
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: Allogamy includes both geitonogamy and xenogamy.
Reason: Allogamy needs abiotic or biotic external agencies for pollination.
→
Read the following and answer any four questions from $(i)$ to $(v)$ given below:
The endosperm makes the main source of food for the embryo. Generally the endosperm nucleus divides after the division of the oospore, but in several cases the endosperm is formed to a great extent even before the first division of the oospore. There are three general types of endosperm formation: $(a)$ nuclear type, $(b)$ cellular type and $(c)$ helobial type. The endosperm is usually triploid, but haploid endosperm is also found. Endosperm may either be completely consumed by the developing embryo before seed maturation, or it may persist in the mature seed.
  1. Haploid endosperm is found in :
  1. Pin us.
  2. Cauliflower.
  3. Sunflower.
  4. Pea.
  1. Persistent endosperm is found in:
$P$. Pea $Q$. Castor $R$. Bean $S.$ Coconut $T$. Groundnut.
  1. $Q$ and $S$.
  2. $P$ and $T$.
  3. $R, S$ and $T$.
  4. $P, S$ and $T$.
  1. Milk of tender coconut represents $(A)$ and the surrounding white coconut meal represents $(B).$
S. No
$A$
$B$
$(a)$
Cellular endosperm
Free- nuclear endosperm
$(b)$
Free $-$ nuclear endosperm
Cellular endosperm
$(c)$
Helobial endosperm
Cellular endosperm
$(d)$
Free-nuclear endosperm
Helobial endosperm
  1. If an endosperm cell of a gymnosperm contains $12$ chromosomes, the number of chromosomes in each cell of the root will be:
  1. $4$
  2. $24$
  3. $16$
  4. $6$
  1. In angiosperms, normally after fertilization:
  1. The zygote divides earlier than the primary endosperm nucleus.
  2. The primary endosperm nucleus divides earlier than the zygote.
  3. Both the zygote and primary endosperm nucleus divide simultaneously.
  4. Both the zygote and primary endosperm nucleus undergo a resting period.
→
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.
→
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: Ribosomes attached to endoplasmic reticulum release proteins into lumen of $\text{ER}.$
Reason: Such proteins are used for formation of hydrolytic enzymes or are modified.
→
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 : Synthesis of tryptophan is self regulatory.
Reason: Tryptophan works both as co$-$repressor and through feedback inhibition.
→
Human insulin is being commercially produced from transgenic species of $...........$
→
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: Aspergillus niger produces lactic acid.
Reason: Rhizopus produces citric acid.
→
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.
→