Explanation

Light travels at about 300,000 kilometers per second in a vacuum with a refractive index of 1.0,

but slows down to 225,000 kilometers per second in water

and 200,000 kilometers per second in the glass.

ND16-3-2023

Explanation

• Inertia is the tendency of an object to resist changes in its motion.
• As described by Newton's First Law of Motion (also known as the Law of Inertia).
• This means that an object at rest will remain at rest, and an object in motion will continue moving in a straight line, unless acted upon by an external force.

Explanation

• Cholera is a waterborne disease caused by the bacterium Vibrio cholerae, which is typically found in contaminated water sources.
• If a child has cholera, it indicates that they have ingested contaminated water.
• It addressing water pollution is crucial to prevent further spread of the disease.

Water pollution can cause:

• Waterborne diseases (cholera, typhoid, diarrhea)
• Death of aquatic life (fishes, animals, plants)
• Health problems (immune depression, reproductive failure, acute poisoning)

Explanation

• Stars generate their own light through nuclear fusion in their cores.
• It making them self-luminous.

Explanation

• Asthma is a respiratory disease that can be triggered or exacerbated by exposure to air pollution.
• Air pollution can irritate the airways, trigger asthma attacks, and make symptoms worse.

Air pollution can cause:

• Respiratory problems: asthma, pneumonia, lung cancer
• Irritation: headaches, eyes and nose irritation, sore throat
• General symptoms: nausea, drowsiness, ill feeling
• Impaired judgment and weakened cognitive function

Explanation

• Light travels in a straight line.
• It is also known as a rectilinear path.
• It in a homogeneous medium like air or vacuum.

Explanation

Frogs can breathe through their skin, lungs, and lining of the mouth, especially in water where cutaneous respiration is key.

This ability helps them absorb oxygen directly from their environment.

Earthworms and amphibians, such as frogs, breathe through their skin. 

Explanation

All electromagnetic waves (like light, X-rays, and radio waves) travel through a vacuum at the same constant speed.

It is approximately 3 × 10⁸ meters per second.

Explanation

Our Sun formed about 4.57 billion years ago from a cloud of gas and dust known as a solar nebula.

This process eventually led to the formation of the entire solar system.

Explanation

Invertebrates are animals that do not have a backbone or spinal column. This group includes:

• Insects
• Arachnids (like spiders and scorpions)
• Crustaceans (like crabs and lobsters)
• Mollusks (like squids and octopuses)
• Echinoderms (like starfish and sea urchins)
• Worms