Explanation

The Battle of Uhud was fought on Saturday, 23 March 625 AD, in the valley north of Mount Uhud.

Abu Sufyan commander of the infidels in  Uhad Ghazwa

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It was fought in 3 Hijri 

Ohad is the name of a mountain

1000 Muslims participated in the battle of Uhad

3000 Infidels participated in the battle of Uhad Infidel means کفار

In the battle of Uhad Prophet Muhammad (PBUH) selected 50Skillful archers to stay on the mountain

Explanation

Abscisic acid is a plant hormone that regulates processes like dormancy and stomatal closure.

It helps plants respond to stress conditions like drought.

Explanation

Seahorse is a true fish; it has gills, fins, and lives in water.

Jellyfish, cuttlefish, and starfish are not true fish despite their names.

Explanation

In 1796, Edward Jenner successfully used material from cowpox to vaccinate against smallpox.

This was the first successful vaccination in medical history.

Explanation

Vitamin K is essential for the synthesis of clotting factors in the blood.

Its deficiency leads to prolonged bleeding or poor blood clotting.

Explanation

In the modern periodic table, there are 7 periods (horizontal rows) and 18 groups (vertical columns).

Explanation

NO₂ (Nitrogen dioxide) is a covalent compound, made of nonmetals (nitrogen and oxygen) sharing electrons.

The others like (NH₄)₂CO₃, HNO₃, and AgCl involve ionic bonding either fully or in part (e.g., NH₄⁺ acts ionically).

Explanation

Dative bond: This is a type of covalent bond where one atom donates both electrons to the bond, forming a coordinate covalent bond.

In this case, NH₃ (ammonia) (with a lone pair of electrons) acts as the electron donor, and BF₃ (boron trifluoride) (electron deficient) acts as the electron acceptor.

Explanation

John Dalton proposed the Atomic Theory in the early 1800s, stating that all elements are made of indivisible atoms.

He described atoms as indestructible and identical for each element, laying the foundation of modern chemistry.

Explanation

A reaction in which heat is absorbed is called an endothermic reaction.

These reactions lower the temperature of their surrounding area, thereby creating a cooling effect.