MyClass24 logo
myclass24
YOUR CLASS. YOUR PACE.
Q&A Bank

Questions & Answers

1,371 answers across all subjects

Subject:MathematicsScienceEnglishSocial StudiesHindiPhysicsChemistryBiologyComputer Science
Class:123456789101112
ScienceClass 8CBSE

How are even small animals important in an ecosystem?

Every organism forms a part of food chain and ecosystem. Hence every organism is important to balance ecosystem.

ScienceClass 8CBSE

Why are endemic organisms in greater danger of becoming extinct?

Endemic organisms are those which can live in particular geographical location. Any disturbance to their natural habitat will affect the endemic animals adversely hence they are in great danger of becoming extinct.

ScienceClass 8CBSE

Why are wildlife sanctuaries important for conservation of plants and animals?

Wildlife sanctuaries important for conservation of plants and animals because in these areas poaching or killing animals, and disturbing animals by any means of human activity are prohibited. More over in wild life sanctuaries animals can live in their natural environment. This promotes their breeding and population increase.

ScienceClass 8CBSE

Can a forest regenerate naturally in a short period of time?

It takes long period of time to regenerate the forest naturally.

ScienceClass 8CBSE

In our country, large patches of forests are being cleared for cultivation of crops. The environmental impact of such a practice will lead to (a) soil erosion (b) soil conservation (c) soil pollution soil fertility

Answer is (a) soil erosion Explanation: Due to cutting of trees, there will no roots to hold the soil, because of this top soil erodes by the action of wind.

ScienceClass 8CBSE

Mention any one action that you have undertaken to conserve trees

Donating old books and spreading awareness about deforestation .

ScienceClass 8CBSE

Why is it important to conserve forests?

Forest should be conserved for balance in nature and to conserve the ecosystem.

ScienceClass 8CBSE

Migratory birds fly to far away areas during a particular time of a year. Which of the following conditions present in their habitat during that time are responsible for this behaviour? (i) Unavailability of food. (ii) (ii) Extreme weather conditions. (iii) (iii) Over crowding. (iv) (iv) Lack of nesting areas. (a) ii & iii; (b) i & ii; (c) i & iv (d) ii & iv.

Answer is (b) i & ii; Explanation: Migration of birds is a process of moving to different habitats due to adverse climatic condition. Because of extreme weather conditions birds fail to gather food and they cannot lay their eggs.

ScienceClass 8CBSE

1. The Red Data Book keeps a record of all the (i) endemic species. (ii) extinct species. (iii) endangered plants (iv) endangered animals. (a) i & ii; (b) ii & iii; (c) iii & iv; i & iv

Soln: Answer is(c) iii & iv Explanation: Red Data book keeps record of endangered animal and endangered plants. Red Data Book is different for plants, animals and other species.

ScienceClass 8CBSE

What do black buck, elephant, python and golden cat together represent in a forest? (a) fauna (b) flora (c) ecosystem species

Soln: Answer is (a) fauna Explanation: Fauna is the animals in a particular area. Flora is the plant species in a particular area. Ecosystem includes physical environment along with plants and animals of a particular area. Species is a group of inbreeding population.

ScienceClass 8CBSE

Which statement is incorrect about endangered species? (a) Their number has decreased drastically. (b) They might become extinct in the near future. (c) They pose a danger to other animals. Their natural habitat needs to be protected

Soln: Answer is (c) They pose a danger to other animals.

ScienceClass 8CBSE

Which of the following feature is correct for a wildlife sanctuary? (a) It is an artificially created protected area for animals. (b) It is a protected area for threatened and endangered wild animals. (c) It is meant for conservation of only plant species. (d) Capturing and poaching of animals is strictly prohibited here.

Soln: Answer is (a) It is an artificially created protected area for animals. Explanation: Wild life sanctuary is an artificially created protected area for animals. Hence option c) is wrong . Wild life sanctuaries are not specific for threatened and endangered wild animals. Hence answer b) is wrong. Capturing and poaching of animals is strictly prohibited everywhere hence option d) is not appropriate.

ScienceClass 8CBSE

Which one of the following statements is true about endemic species? (a) They are found exclusively in a specific habitat. (b) Endemic species can never become endangered. (c) They are found only in zoos and botanical gardens. (d) They are not affected by the destruction of their habitat.

Soln: Answer is (a) They are found exclusively in a specific habitat. Explanation: Endemic species are those which are found exclusively in a specific habitat. Endemic species get extinct when habitat is destroyed by human activities or by introduction of new species is introduced to the habitat.

ScienceClass 8CBSE

The place meant for conservation of biodiversity in their natural habitat are (i) Zoological garden (ii) Botanical garden (iii) Wildlife sanctuary (iv) National park (a) i & ii; (b) ii & iii; (c) iii & iv; i & iv

Answer is (c) iii & iv; Explanation: In botanical garden and zoological parks species are protect outside their natural habitat and its ex-situ conservation. On the other hand Wildlife sanctuary and National park are in-situ conservation where conservation of biodiversity occurs in their natural habitat.

ScienceClass 8CBSE

Which one of the following statements is true about a Biosphere Reserve? (a) It is a protected area where only endemic species live. (b) It is meant only for the conservation of plants and animals. (c) It is meant to conserve both, the biodiversity and the culture of that area. (d) There are no other protected areas within its limits.

Answer is (c) It is meant to conserve both, the biodiversity and the culture of that area. Explanation: Biosphere reserve is the protected part of land covered with forests. It is meant for the conservation of wild life, biodiversity and traditional lifestyle of tribals.

ScienceClass 8CBSE

Which one of the following changes may occur due to desertification? (a) Decrease in atmospheric temperature. (b) Increase in water holding capacity of soil. (c) Increased chances of floods. (d) Conversion of fertile land into a desert.

Answer is (d) Conversion of fertile land into a desert. Explanation: Soil is carried away by wind when there are no trees as there will be no roots to hold onto the soil. Thus top soil erodes out which will turn the land to desert.

ScienceClass 8CBSE

Wild buffalo is an endangered species because (a) its population is diminishing (b) it has become extinct (c) it is found exclusively in a particular area its poaching is strictly prohibited

Answer is (a) its population is diminishing Explanation: Endangered species are those whose population is diminishing at an alarming rate and they may face extinction in near future.

ScienceClass 8CBSE

Hens and frogs are both oviparous exhibiting different types of fertilisation. Explain.

In Hens internal fertilisation takes place. Fertilised egg develops inside female body but development of chick from the embryo takes place outside the body. On the other hand in frogs both fertilisation and development of zygote to embryo and young ones occurs outside the body.

ScienceClass 8CBSE

Why do only male gametes have a tail?

Because sperm need to be motile to reach non-motile egg in the ovary of female.

ScienceClass 8CBSE

State whether the following statements are True or False. If false, correct the statement: (a) External fertilisation can occur both in water and on land. (b) The eggs of fish are covered by hard shells for protection. (c) Human egg has a head, middle piece and tail. (d) In adult human females, a single mature egg is released into an oviduct every month.

False- External fertilisation can occur only in False- eggs of fish are covered by jelly like substance for False- Human sperm has a head, middle piece and True

12345678910