Tag: zoology

Quizzes (289) Questions (5869)

Questions Related to zoology

Multiple choice zoology allotropy of oxygen ozone - a case study stratospheric pollution ozone and its depletion

In the stratosphere, what does screen out a large fraction of the ultraviolet rays of the sun?

  1. $H _2$
  2. $SO _2$
  3. $CO$
  4. $HCl$
  5. $O _3$
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

In the stratosphere, ozone $\displaystyle O _3 $ screen out a large fraction of the ultraviolet rays of the sun. Thus, ozone acts as a protective shield. Thus, due to presence of ozone layer, the harmful ultraviolet rays cannot penetrate earth's atmosphere. Hence, they cannot reach us.

Multiple choice zoology allotropy of oxygen ozone - a case study stratospheric pollution ozone and its depletion

Ozone deplete due to the formation of following compound in antartica?

  1. Acrolein

  2. peroxy acetyl nitrate
  3. $SO _2$ and $SO _3$

  4. Chlorine nitrate
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The ozone depletion was related to halogen (chlorine)-catalyzed chemical reaction which takes place in the spring season in the Antarctic polar region. The chlorine is derived from manmade chlorofluorocarbons and reacts with nitric acid forms chlorine nitrate($ClONO _2$) (CFCs) in the stratosphere.

Hence option D is correct. 

Multiple choice zoology allotropy of oxygen ozone - a case study stratospheric pollution ozone and its depletion

The two forms of oxygen found in the atmosphere are:

  1. Water and ozone

  2. Water and oxygen

  3. Ozone and oxygen

  4. Water and carbon-dioxide
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The two forms of oxygen found in the atmosphere are a diatomic molecular form that has chemical formula as O$ _2$ or oxygen, the life-giving gas that we breathe in to survive. 
Another  is a triatomic molecular form that has chemical formula as O$ _3$ called ozone gas, it protects us from harmful UV rays.
In water, oxygen is found as a compound with hydrogen molecules. The oxygen in water is dissolved oxygen used by aquatic animals and plants.
carbon dioxide has 2 molecules of oxygen with one molecule of carbon. It is formed by the reaction between carbon molecules and oxygen molecules during fermentation or respiration.
In the case of water and carbon dioxide, the oxygen does not exist independently but in association with other molecules. Whereas in the case of ozone and oxygen, the oxygen exists independently. Hence, the two forms of oxygen are ozone and oxygen.
The correct option is C (Ozone and Oxygen).

Multiple choice zoology allotropy of oxygen ozone - a case study stratospheric pollution ozone and its depletion

In which part of the atmosphere, ozone layer is present ?

  1. Stratosphere

  2. Troposphere

  3. Mesosphere

  4. Thermosphere
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The ozone layer or ozone shield refers to a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet (UV) radiation. It contains high concentrations of ozone ($O _3$) relative to other parts of the atmosphere, although still very small relative to other gases in the stratosphere. 

Multiple choice zoology allotropy of oxygen ozone - a case study stratospheric pollution ozone and its depletion

Ozone is an important constituent of stratosphere because it:

  1. prevents the formation of smog over large cities

  2. removes poisonous gases of the atmosphere by reacting with them

  3. absorbs ultraviolet radiations which is harmful to human life

  4. destroys bacteria which are harmful to human life
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
The stratospheric ozone layer absorbs ultraviolet light (UV) emitted by the sun. If the solar UV light were able to penetrate the stratosphere and troposphere and reach the earth’s surface, it would seriously damage our ecosystem.
And also it causes skin cancer, blindness, and cataracts.
Hence, the correct option is C.
Multiple choice zoology allotropy of oxygen ozone - a case study stratospheric pollution ozone and its depletion

Which of the following is responsible for peeling of ozone umbrella?

  1. PAN

  2. Coal burning

  3. CFCs
  4. ${CO} _{2}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
$ The\quad correct\quad answer\quad is\quad "CFCs".$

$CFCs\quad drift\quad slowly\quad upward\quad to\quad the\quad stratosphere,where\quad they\quad are\quad broken\quad up\quad by\quad ultraviolet\quad radiation,releasing\quad chlorine\quad atoms,which\quad are\quad able\quad to\quad destroy\quad Ozone\quad molecules.The\quad chlorine\quad atom\quad then\quad reacts\quad with\quad anozone(O3)molecule\quad breaking\quad it\quad apart\quad and\quad so\quad destroying\quad the\quad ozone.$\\

$A\quad single\quad CFCs\quad molecule\quad can\quad destroy\quad 100,000\quad ozone\quad molecules.$
Multiple choice zoology allotropy of oxygen ozone - a case study stratospheric pollution ozone and its depletion

Which of the following statements is correct?

  1. Ozone hole is a hole formed in stratosphere from which ozone oozes out

  2. Ozone hole is a hole formed in troposphere from which ozone oozes out

  3. Ozone hole is thinning of ozone layer of stratosphere at some places

  4. Ozone hole means vanishing of ozone layer around the earth completely.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
The correct answer is Ozone hole is thinning of an ozone layer of the stratosphere at some places

The ozone hole is formed mainly from the two types of compounds which are responsible for the depletion of the ozone layer.
 These are:-
  • NO'S
  • CFC'S(Chlorofluorocarbons)
$N{ O } _{ 2 }+{ O } _{ 3 }\longrightarrow N{ O } _{ 2 }+{ O } _{ 2\\  }$
$C{ F } _{ 2 }C{ l } _{ 2 }\longrightarrow { CF } _{ 2 }Cl\quad +Cl$
$\dot { Cl } +{ O } _{ 3 }\longrightarrow Cl\dot { O } +{ O } _{ 2 }$
$Cl\quad +\dot { O\longrightarrow  } C\dot { l } +{ O } _{ 2 }$
These reactions occur in the stratosphere.
Multiple choice zoology bio-geo chemical cycles in nature nitrogen cycle biogeochemical cycles - gaseous nutrient cycles

Reaction carried out by $N _2$ fixing microbes include
$2NH _3 + 3O _2 \rightarrow 2NO _2^- + 2H^+ + 2H _2O$            (i)
$2NO _2^- + O _2 \rightarrow 2NO _3^-$                                       (ii)
Which of the following statements about these equations is not true?

  1. Step (i) is carried out by Nitrosomonas or Nitrosococcus

  2. Step (ii) is carried out by Nitrobacter

  3. Both step (i) and (ii) can be called nitrification.

  4. Bacteria carrying out these steps are usually photoautotrophs.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Phototrophic bacteria are a group of bacteria, whose energy for growth is derived from sunlight and their source of carbon comes from carbon dioxide or organic carbon.
So, the correct option is 'Bacteria carrying out these steps are usually photoautotrophs'.
Multiple choice zoology bio-geo chemical cycles in nature nitrogen cycle biogeochemical cycles - gaseous nutrient cycles

A farmer adds Azotobacter culture to soil before sowing maize. Which mineral element will be replenished by doing so?

  1. N

  2. P

  3. K

  4. S
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Azotobacter is a free living bacteria in the soil. It helps some cereal crops like maize (Zea mays) in nitrogen fixation. The farmer adds Azotobacter culture to the maize field for enhancing the nitrogen element in the soil by the process of biological nitrogen-fixation. 
Thus, the correct answer is 'N.'

Multiple choice zoology bio-geo chemical cycles in nature nitrogen cycle biogeochemical cycles - gaseous nutrient cycles

Which of the following is a non-symbiotic nitrogen fixing prokaryote?

  1. Azotobacter

  2. Clostridium

  3. Beijerinckia

  4. All of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Two kinds of nitrogen-fixing bacteria are recognized. The first kind, the free-living (non-symbiotic) bacteria, includes the cyanobacteria (or blue-green algae), Anabaena and Nostoc and genera such as Azotobacter, Beijerinckia, and Clostridium. 

Thus, the correct answers is 'All of these.'