A technique in which the muscles are stretched by an outside force is called Passive Stretching
I would assume that the magnesium would have to come into contact with an ion in order to become a magnesium ion.
Generally, rings form from moons, asteroids, or comets that have disintegrated due to a collision or because they got too close to their planet (Roche Limit). ... Most of the debris, however, will not have enough energy to overcome the planet's gravity and will remain in orbit around the planet.
Answer:
They have a dual wave-particle nature.
Explanation:
Electromagnetic waves consist of periodic oscillations of electric and magnetic field in a plane perpendicular to the direction of motion of the wave (in fact, they are also classified as transverse waves).
Electromagnetic waves have a wave nature, however they also have particle nature - in fact, it has been proved in some experiment (e.g. photoelectric effect) that in some conditions they act as packets of particles - called photons. Therefore, the option
They have a dual wave-particle nature.
is correct.
Other options are wrong because:
They are all invisible. --> False because visible light (which is part of the electromagnetic spectrum, so they are electromagnetic waves) is visible
They can only travel without a medium. --> False because they can also travel in a vacuum
They are slower than sound waves. --> False because they travel much faster (they travel at the speed of light in a vacuum, 
, while sound travels at 343 m/s in air, for instance)
Answer:
Gravitational pull
Explanation:
There are four fundamental forces in nature:
- Gravitational force: it is an attractive force exerted between all objects having mass. Its magnitude is proportional to the product of the masses and inversely proportional to the square of the distance between the objects.
- Electromagnetic force: it is the force exerted between electrically charged object. It can be either attractive ore repulsive. Its magnitude is proportional to the product of the charges and inversely proportional to the square of the distance between the objects.
- Strong nuclear force: it is the force responsible for holding protons and neutrons together in the nuclei of the atoms. It is attractive and acts only on a very short scale.
- Weak nuclear force: it is the force responsible for certain nuclear decay processes (radioactivity).
In this problem, landslides occur when certain masses of terrain are attracted towards the ground - they are attracted because of the gravitational force.
So, the correct answer is
gravitational pull
