Answer: Option A. ->
:

Endangered species are species that are under the threat of extinction. This can occur if the rate in which they are reducing in number is greater than their rate of reproduction. Human activities caused a drastic loss in wildlife habitat, forcing many species such as tiger, black rhino, orangutan, etc., to the verge of extinction.

Answer: Option A. -> Climate change
:
A, B, and D
The enhanced greenhouse effect is the impact on the climate from the additional heat retained due to the increased amounts of carbon dioxide and other greenhouse gases that humans have released into the earths atmosphere due to increased industrialisation, burning of fossil fuels and modern means of transport thus causing global warming. It leads to melting of polar ice caps and also rise in sea level.

Answer: Option A. -> End of a species
:
A and B

 Extinction of a particular animal or plant species occurs when there are no more individuals of that species living anywhere in the world. Sometimes, extinction happens at a much faster rate than usual.

Answer: Option B. -> Biodiversity
:
B

Biodiversity refers to the variety of organisms existing on the earth, their interrelationships and their relationship with the environment. Biodiversity or Biological diversity is a term that describes the variety of living beings on earth. It helps in maintaining the balance of the ecosystem.

Answer: Option A. -> Flora of that area
:
A

The sum of plant species in a given area or time is called flora of that area. For example sal, teak, mango, jamun, silver ferns, arjun, etc., are the flora, which means the plant species in that particular area.

Answer: Option D. -> migratory birds
:
D

Birds travelling long distances seasonally, to reach faraway lands with suitable climate conditions, are called migratory birds. They migrate each year at a particular season to escape from harsh climatic conditions. Examples of migratory birds include the Arctic tern and Siberian crane.

Answer: Option B. -> False
:
B
The roots of trees firmly hold the topmost layer of the soil. They do not allow natural forces like wind, water, etc., to carry away the top most fertile layer of the soil easily. Afforestation refers to the planting of trees in an area, which will prevent soil erosion.

Answer: Option A. -> Lists of species whose continued existence is threatened
:
A

Red Data Book contains list of species whose continued existence is threatened. Species are classified into different categories of perceived risk. Each Red Data Book usually deals with a specific group of animals or plants (eg: reptiles, insects, mosses). The Red Data Book contains color-coded information sheets, which are arranged according to the extent the species is in danger. The black coloured sheet for species which are extinct, red coloured sheet for species that are in more danger, amber coloured for species, which are getting attacked by other species, white coloured for very rare species, green coloured for species, not in danger and grey coloured for the species that are intimated to be vulnerable, endangered, or rare.

Answer: Option C. -> endemic
:
C

Endemic species are those species of plants or animals which are found exclusively in a particular area. They are not naturally found anywhere else. A particular type of animal or plant may be endemic to a zone, a state or a country. For example, kangaroos are endemic to Australia.

Answer: Option A. -> True
:
A
Deforestation means, cutting down of trees which affects the soil properties. The fertile top layer is removed which exposes the lower layers which have less humus and is less fertile. Due to this, the fertile land gets converted into deserts and this process is called desertification.