Explanation

Elements or compounds that combine in a chemical reaction are called reactants.

Explanation

The pH of pure water (H20) is 7 at 25 °C

pH stands for "Potential Hydrogen"

Explanation

• Chemical digestion of proteins begins in the stomach
• Mechanical digestion (chewing) starts in the mouth,
• The chemical breakdown requires gastric juices, specifically hydrochloric acid (HCL)
• The enzyme pepsin activates and breaks down protein molecules.

Last updated by NS on 20-April-2026

Explanation

The angle sum of a triangle will always be equal to 180°.

The angle sum of a quadrilateral is equal to 360°

And a triangle can be created by slicing a quadrilateral in half from corner to corner. Since a triangle is essentially half of a quadrilateral

Its angle measures should be half as well. Half of 360° is 180°

Explanation

Oxygen has 8 protons and typically 8 neutrons, giving it a mass number of 16.

Mass number = Number of protons + Number of neutrons.

Symbol: O

Atomic number: 8

Discoverers: Joseph Priestley, Carl Wilhelm Scheele

Electrons per shell: 2, 6

Discovered: 1774

Appearance: gas: colorless; liquid and solid: pale blue

Explanation

Evaporation is the process where liquid turns into gas at temperatures below its boiling point.

It occurs at the surface of the liquid.

It is influenced by factors like temperature and surface area.

Explanation

Garbage means کچرا

Litter means گندگی

Explanation

Laugh is an intransitive verb and does not take any object.

Laughed is the second and third form of Laugh.

Explanation

"Or" is used to show a choice or alternative between two options: hardworking or lazy.

The sentence is asking which one applies, not contrasting or adding, so "or" fits best.

Explanation

According to Behavior learning theory, motivation is seen as a consequence of reinforcement, where behaviors are shaped and maintained by rewards or punishments.

Reinforcement strengthens the likelihood of a behavior being repeated, thus driving motivation.