C++ | MCQs

Explanation

A compound machine is a machine that is made up of two or more simple machines.

A bicycle, a crane, wheel borrow and scissors are examples of compound machines because they are made up of multiple simple machines, such as:

• Wheels and axles (simple machine: wheel)
• Pedals and levers (simple machine: lever)
• Gears and pulleys (simple machine: pulley)
• Inclined planes (simple machine: inclined plane)

Explanation

• Laboratory thermometers typically have a lower temperature range than clinical thermometers, and are designed to measure temperatures in a laboratory setting.
• The lowest temperature in a laboratory thermometer is often around -10°C or even lower, depending on the specific thermometer.

Explanation

• The freezing point of water is 0°C (zero degrees Centigrade). 
• The boiling point of water is 100°C (one hundred degrees Centigrade).

Explanation

When you put sand, salt, and sawdust in a glass of water, the following things happen:

• Salt dissolves in water, meaning it breaks down into individual particles that are distributed evenly throughout the water.
• Sand sinks to the bottom of the glass, because it is denser than water and cannot float or dissolve in it.
• Sawdust floats on top of the water, because it is less dense than water and is able to remain suspended on the surface.

Explanation

• Water (H2O) is a compound made up of two hydrogen atoms and one oxygen atom.
• It is a chemical combination of two different elements, which is the definition of a compound.

Explanation

• Liquids can be converted into solids by cooling, a process known as freezing or solidification.
• As the temperature decreases, the particles of the liquid slow down and come together, forming a solid.

Explanation

• Liquids take the shape of a container because they have a fixed volume but no fixed shape.
• They conform to the shape of the container they are placed in.

Explanation

• Gases are the state of matter that takes both the shape and volume of a container they are placed in. They expand to fill the container and conform to its shape.
• Liquids, take the shape of a container but maintain their own volume.
• Solids maintain both their shape and volume, regardless of the container they are placed in.

Explanation

• Frogs are heterotrophic animals that obtain energy by consuming other organisms, such as insects, worms, and even smaller frogs.
• They do not produce their own food like plants (producers) do, and they do not break down dead organisms like decomposers (such as bacteria and fungi) do.
• Therefore, the best description for a frog is a consumer.

Explanation

• Human beings are omnivores because we eat a variety of foods including plants (fruits, vegetables, grains), animals (meat, poultry, fish), and products derived from animals (dairy, eggs).