Explanation

• A Barometer is an instrument used to measure air (atmospheric) pressure.
• It helps in weather forecasting by measuring changes in atmospheric pressure.
• The mercury barometer is the oldest type of barometer.
• It was invented by Evangelista Torricelli in 1643.
• Barometers are widely used in meteorology and aviation.

Last verified on 09-07-2026

Explanation

• Vitamin C deficiency causes scurvy.
• It can cause bleeding/loose gums, easy bruising, and poor wound healing.
• Other signs include rough skin, corkscrew hair, and red spots around hair follicles.
• Rickets is mainly caused by Vitamin D deficiency.

Last verified on 13-09-2026

Explanation

• Insulin is produced by the pancreas.
• The pancreas contains clusters of cells called the Islets of Langerhans.
• Beta (β) cells within these islets produce and secrete insulin.
• Insulin helps regulate blood glucose (sugar) levels by promoting glucose uptake into cells.

Last verified on 07-09-2026

Explanation

• Carbon dioxide (CO₂) — the main greenhouse gas causing global warming.

Additional information:

• Methane (CH₄) — potent, from livestock and fossil fuels.
• Nitrous oxide (N₂O) — from fertilizers and industry.
• Water vapor — natural, amplifies warming.
• Fluorinated gases — synthetic, very strong effect.

Explanation

• Heinrich Wilhelm Waldeyer coined the word "neuron" in 1891.
• He based it on the ancient Greek word for sinew or cord.
  
• Neuron theory/doctrine emerged at the end of the 19th century.
• Core claim — Nerve tissue = individual cells; each is a genetic, anatomic, functional, and trophic unit.
  
  Last updated by NA on 09-09-2026