Insights Static Quiz -180, 2018 –Environment

Solution: a)

• In-situ conservation, the conservation of species in their natural habitats. It includes National parks, wildlife sanctuaries, biosphere reserves and sacred groves (Khasi and Jaintia hills in Meghalaya).
• Ex-situ conservation is the preservation of components of biological diversity outside their natural habitats. It includes Gene banks, Captive breeding of animals and artificial propagation of plants, zoos, aquaria, and botanic gardens.

Solution: b)

Polar stratospheric clouds (PSCs) play a central role in the formation of the ozone hole in the Antarctic and Arctic. PSCs provide surfaces upon which heterogeneous chemical reactions take place. These reactions lead to the production of free radicals of chlorine in the stratosphere which directly destroy ozone molecules.

Solution: b)

Mulching is a protective covering, as of bark chips, straw, or plastic sheeting, placed on the ground around plants to suppress weed growth, retain soil moisture, or prevent freezing of roots.

Advantages: ·  Mulching improves nutrient and water retention in the soil. ·  Encourages favourable soil microbial activity and worms. ·  Suppresses weed growth. ·  Mulching reduces evaporation. ·  Mulch also helps to retain moisture, prevent soil erosion, control weeds and it adds nutrients to the soil.

Solution: c)

Statement 1: Biological weathering is contribution to or removal of minerals and ions from the weathering environment and physical changes due to growth or movement of organisms.

Burrowing and wedging by organisms like earthworms, termites, rodents etc., help in exposing the new surfaces to chemical attack and assists in the penetration of moisture and air.

Decaying plant and animal matter help in the production of humic, carbonic and other acids which

enhance decay and solubility of some elements. Plant roots exert a tremendous pressure on the

earth materials mechanically breaking them apart

Statement 2: Weathering processes are responsible for breaking down the rocks into smaller

fragments and preparing the way for formation of not only soils, but also erosion and

mass movements.

Erosion cannot be significant if the rocks are not weathered. That means, weathering aids mass

wasting, erosion and reduction of relief and changes in landforms are a consequence of erosion.

Solution: c)

• The term heavymetal refers to any metallic chemical element that has a relatively high density and is toxic or poisonous at low concentrations. Examples of heavy metals include mercury (Hg), cadmium (Cd), arsenic (As), chromium (Cr), thallium (Tl), and lead (Pb).
• Heavy metals are natural components of the Earth’s crust. They cannot be degraded or destroyed.
• Chromium is used in metal alloys and pigments for paints, cement, paper, rubber, and other materials.
  Cadmium is present in several products, including fertilisers, detergents and refined petroleum products.