<span>the answer is :
permanent magnets
</span>A permanent magnet<span> is an object made from a material that is </span>magnetized<span> and creates its own persistent magnetic field. An everyday example is a </span>refrigerator magnet<span> used to hold notes on a refrigerator door. Materials that can be magnetized, which are also the ones that are strongly attracted to a magnet, are called </span>ferromagnetic<span> (or </span>ferrimagnetic<span>). These include </span>iron<span>, </span>nickel<span>, </span>cobalt<span>, some alloys of </span>rare-earth metals<span>, and some naturally occurring minerals such as </span>lodestone<span>. Although ferromagnetic (and ferrimagnetic) materials are the only ones attracted to a magnet strongly enough to be commonly considered magnetic, all other substances respond weakly to a magnetic field, by one of several other types of </span>magnetism<span>.</span>
Answer:
It is important to understand the difference between rotations and revolutions. When an object turns around an internal axis (like the Earth turns around its axis) it is called a rotation. When an object circles an external axis (like the Earth circles the sun) it is called a revolution.
Answer:
The correct answer is option d
Explanation:
Answer: Behavioral isolation.
Mechanical isolation. ...
Temporal isolation
The guard-condition on a transition indicates that<span> if the specified trigger event occurs and the specified </span>guard condition<span> is true.</span>
