Explanation

AUG is the start codon in mRNA that signals the beginning of protein synthesis.

It codes for the amino acid Methionine in eukaryotes.

During translation, ribosomes recognize AUG to initiate protein assembly.

Stop codons like UAA, UAG, and UGA signal the end of translation.

Explanation

The chemical name for quartz is silicon dioxide

Chemical Formula: SiO₂

Composition: Silicon (Si) and Oxygen (O)

Structure: A framework of silicon-oxygen tetrahedra

Common Names: Silica, Rock Crystal (for the clear variety)

Explanation

Enzymes are proteins in nature.

Proteins are composed of one or more polypeptide chains.

The polypeptide folds into a specific three-dimensional shape.

This shape determines the enzyme’s active site and function.

Therefore, the basic structure of an enzyme is a polypeptide.

Explanation

Oxygen is a vital component of the Earth's atmosphere (making up about 21%) and is essential for life

Therefore, oxygen is not considered a part of smog.

Smog in Pakistan mainly consists of harmful air pollutants.

These include sulphur dioxide, nitrogen oxides, and carbon monoxide.

Explanation

Christiaan Huygens (1629–1695) proposed the wave theory of light.

He suggested that light travels in the form of waves, not particles.

Huygens’ principle explains how light waves propagate, reflect, and refract.

This theory challenged Newton’s particle theory of light.

Explanation

A covalent bond is formed when two atoms share one or more pairs of electrons.

This sharing creates a strong bond between the atoms, holding molecules together.

Explanation

Bees must collect nectar from approximately 2 million flowers to make 1 pound of honey.

This immense effort requires bees to fly roughly 55,000 to 90,000 miles

A honey bee visits 50 to 100 flowers during a single,, dedicated collection trip.

Production Context: It takes approximately 556 worker bees to gather enough nectar for 1 pound of honey. 

Explanation

Infiltration is the process by which water enters the soil from the surface.

It helps replenish groundwater and maintain soil moisture.

Additional information 

Percolation is the downward movement of water through soil layers.

Evaporation is the conversion of water into vapor, and transpiration is water loss from plants.

Explanation

An ecosystem develops through a series of successional stages.

The final, stable stage is called the climax community.

It is characterized by a balanced and self-sustaining ecosystem.

Explanation

Brackish water is a mixture of fresh water and salt water

It is most commonly found in estuaries

The salinity in estuaries is higher than freshwater but lower than seawater.