Explanation

Railway tracks are made of steel, which expands in summer heat.

The gaps between rails allow space for this expansion, preventing the tracks from buckling or derailing trains.

Explanation

Insulin is produced by the pancreas, which is an organ located behind the stomach.

The pancreas contains clusters of cells called the Islets of Langerhans, specifically the beta cells within these islets, which are responsible for producing insulin.

Insulin plays a crucial role in regulating blood sugar levels by facilitating the uptake of glucose into cells for energy production or storage.

When blood sugar levels rise after a meal, the pancreas releases insulin to help lower blood sugar levels by promoting the uptake of glucose into cells.

Explanation

Benjamin Franklin invented the lightning rod, a device used to protect buildings from lightning strikes.

He made this invention in 1752 as part of his experiments with electricity.

Explanation

Neutrons have no electric charge, hence they are neutral.

Protons have a positive charge.

Electrons have a negative charge.

Explanation

Polythene is a thermoplastic because it softens when heated and can be reshaped.

It is formed by polymerization of ethene molecules.

Explanation

• The spine has 33 stacked vertebrae (small bones) that form the spinal canal. 

• The vertebrae are numbered and divided into regions: cervical, thoracic, lumbar, sacrum, and coccyx.

• Only the top 24 bones are moveable; the vertebrae of the sacrum and coccyx are fused.
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Additional Information "Important For exam point of view"

• The femur is the longest bone in the human body and the shortest bone is the stapes found in the middle ear. 
• A newborn child has 300 bones.
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• The human skull is generally considered to consist of twenty-two bones—eight cranial bones and fourteen facial skeleton bones.
• The human hand has 27 bones
  

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Explanation

A balloon is filled with a gas called helium.

while

A balloon filled with hydrogen gas moves in the upward direction

Explanation

Explanation

Explanation

• An aqueous solution is one where water acts as the solvent, dissolving the solute.
• This type of solution is common in many chemical reactions and biological processes.