Answer:
Explanation: the major difference between an electromagnet and permanent magnet is that the former can have a magnetic field when electric current flows through it and disappears when the flow of the current stops. ... It will always displays the magnetic behaviour.
Answer:
The magnification is 
Explanation:
From the question we are told that
The power of the lens is 
Generally 
The object distance is
the negative sign is because the distance is measured in the opposite direction of incident light (i.e away )
Generally the focal length is mathematically represented as
=>
=> 
converting to cm
=> 
Generally from lens equation we have that

=> 
=> 
Generally the magnification is mathematically represented as

=> 
=> 
A. The particles are packed more tightly in materials with more density which causes the vibrations to bounce of the partials more rapidly which makes them go faster
Since, the options are not given the question is incomplete the complete question is as follows.:
Which of the following is a major way in which oceans contribute to weather systems?
provide a diverse habitat for many organisms
experience changes in amounts of dissolved salts
store and transport the Sun's heat energy
reach depths that can be as much as 12000 meters
Answer: Store and transport the Sun's heat energy.
Explanation:
Oceanic currents are just like a conveyor belt. It helps in transportation of the warm water and the precipitation from the equator to the poles and the cold water in the poles towards the tropics. This way the oceans counteract the uneven distribution of the radiation of sun that reaches upto the surface earth. This will regulate the global climate.
Assemblage is an additive process where artists construct work by putting together objects and attaches them in some way. The correct option among all the options that are given in the question is the second option or option "b". This kind of artistry actually gives a three dimensional impression to the work that is done by the artist.