Answer:
C) electromagnetic waves must have a medium in which to travel, but sound waves can travel anywhere.
Explanation:
Electromagnetic waves do not require a medium to travel. they can travel through vacuum also. for example:- light wave is an electromagnetic wave and it can travel through vacuum also.
On the other hand, sound wave require a medium to travel. sound waves can not travel through vacuum.
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Answer:
Lightning can be best described as an electrical discharge, which is caused by the imbalances between the clouds and the storm and the ground or sometime within the cloud. It carries around 20,000 to 30,000 ampere of current when it comes to the ground.
It is not only the direct hit of the lightning that make you worry, but any strike that is close to us can be dangerous to us as it results in the release of huge amount of electricity in the surrounding area.
It will probably take the highest roll in the food chain which then factors to the other animals either dying, or competing for resources. making the ecosystem unstable.
Answer:
Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: water 
Physical property is defined as the property of a substance which becomes evident during physical changes. Water is liquid at room temperature whereas hydrogen and oxygen are gases at room temperature.
Chemical property is defined as the property of a substance which becomes evident during chemical changes. Water reacts with metals to form bases, hydrogen reacts with metals to form hydrides and oxygen reacts with metals to form oxides.
