Hard and Heavy Water, Climate and Weather, Cardiac and Skeletal Muscles

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Hard Water

  • Hard water is that type of water which does not form lather easily.
  • Its formula is .
  • Hard water is not used in nuclear power plants.

Heavy Water

  • Heavy water is deuterium oxide in which hydrogen of water is replaced by its heavier isotope, Deuterium.
  • The formula of heavy water is .
  • Heavy water is used in nuclear power plants.

Climate & Weather


Climate is the normal weather conditions for an area during a season or a year. ii) Climate of an area is described by means of an average means of an average of the statistics of the various weather factors over a period of time, normally 30-years.


  • Weather is the condition of the atmosphere at any one place and time.
  • Weather is described by air, temperature and humidity, wind speed and direction, cloud amount and precipitation, sunshine and visibility.

Cardiac & Skeletal Muscles

Cardiac Muscles

  • Cardiac muscles are present in the heart only.
  • They have centrally placed nuclei.
  • They never fatigue.
  • They are composed of long fibers.
  • They are under involuntary control.

Skeletal Muscles

  • Skeletal muscles are present in the skeleton of the body.
  • Nuclei are not centrally placed in skeletal muscle.
  • They can fatigue.
  • They are not composed of long fibers.
  • They are under voluntary control.

Haze & Smog


  • The dust particle smoke etc. that may be visible in atmosphere close to the earth՚s surface is known as Haze.
  • It does not affect natural visibility.
  • It does not occur particularly near coastal areas.


  • It is a mixture of solid and liquid fog as well as particles of smoke. It is formed when humidity is high.
  • Smog reduces visibility.
  • It occurs near coastal areas.

Enzyme & Hormone


  • These are organic catalysts produced in the protoplasm of all living cells.
  • These are mostly protein in nature.
  • They control all biochemical reactions of the cell.
  • These are present in all cells and show their activity there.


  • These are organic substances produced in places away from their functional sites.
  • These are mostly acids.
  • They promote and inhibit growth, flowering, sex expression, etc.
  • These are mobile. They are produced at one site and show their activities at other sites.

Igneous & Sedimentary Rocks

Igneous Rocks

  • Igneous rocks are formed when magma (or molten rocks) has cooled down and solidified.
  • Igneous rocks are commonly found inside the Earth՚s crust or mantle,
  • Igneous rocks can be an important source of minerals,
  • Examples of Igneous rocks include granite and basalt.

Sedimentary Rocks

  • Sedimentary rocks are formed by the accumulation of other eroded substances, ii) Sedimentary rocks are usually found in water bodies (sea, oceans etc.) .
  • Sedimentary rocks, or their bedding structure, are mostly used in civil engineering; for the construction of housing, roads, tunnels, canals etc. iv) Examples of Sedimentary rocks include shale, limestone and sandstone.
  • OR What is the difference between Igneous Rocks and Sedimentary Rocks? - Igneous rocks are formed from molten liquid minerals called magma, while sedimentary rocks are formed from lithification (cementing, compacting and hardening) of existing rocks.
  • Igneous rocks are non-porous for water, while sedimentary rocks are porous to the water. That is water cannot penetrate through igneous rocks but can through sedimentary rocks.
  • Igneous rocks are having fossils very rarely, while sedimentary rocks are rich in fossils.
  • Igneous rocks are harder than sedimentary rocks.
  • Tendency to react with acids is higher to sedimentary rocks when compared to igneous rocks.
  • Igneous rocks may be light or dark colored, while sedimentary rocks have great color variety.

Producers & Consumers


Producers are organisms that make their own food through photosynthesis or other reactions and are a food source for other organisms (ex. plants, extremophile benthos communities) .


Consumers are organisms that ingest other organisms, like plants, in order to gain energy (ex. herbivores, carnivores, omnivores, and derivers) .

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