Explanation

The study of coins is called numismatics.

The term "numismatics" was first coined in the late 19th century,

Explanation

Neptune's color is blue.

This is because Neptune's methane atmosphere absorbs red and infrared light.

Explanation

Hummingbirds are birds native to the Americas and constituting the biological family Trochilidae.

They are the smallest of birds, most species measuring 7.5–13 cm (3–5 in) in length.

Explanation

The wavelength of the audible frequency (20 Hz to 20 kHz) audible to the human ear is approximately 17 m to 17 mm.

Bats use slightly higher frequencies, so they can solve targets smaller than 17mm.

The wavelength of audible sound is much longer than the wavelength of visible light.

Explanation

The basic unit of electricity is the Kilowatt hour . In simple terms, 1 kWh is the amount of energy used by a 1kW (1000 watt) electric heater for 1 hour.

Explanation

A beta particle, also called beta ray or beta radiation (symbol β), is a high-energy, high-speed electrons emitted by the radioactive decay of an atomic nucleus during the process of beta decay.

Explanation

Parasitism is a type of relationship where one organism (the parasite) lives on or inside another organism (the host)

And benefits at the expense of the host, who is harmed by the interaction. 

Explanation

The lithosphere is a rigid, rocky outer layer of the Earth.

It consisting of the crust and the solid outermost layer of the upper mantle.

It extends to a depth of about 60 miles (100 km).

Explanation

An ocean current is a continuous, directed movement of seawater.

Ocean current is generated by:

• A number of forces acting upon the water including wind
• The Coriolis effect
• Breaking waves
• Cabbeling
• Temperature and salinity differences.

Additional Information:

Ocean floods:

Coastal flooding occurs when dry and low-lying land is submerged (flooded) by seawater

Cyclone:

Cyclones are caused by atmospheric disturbances around a low-pressure area distinguished and often destructive air circulation.

Tsunami:

Tsunamis are giant waves caused by earthquakes or volcanic eruptions under the sea.

Explanation

A seismograph is an instrument used to detect and record earthquakes.

It consists of a mass attached to a fixed base

During an earthquake, the base moves and the mass does not.