Magma tends to rise toward earth's surface principally because magma tends to rise toward earth's surface principally because of convection in the mantle silica increases the viscosity of the magma rocks become less dense when they melt water is an abundant constituent of magma

Rocks become less dense when they melt.

Explanation:

Magma tends to rise toward Earth's surface principally because rocks become less dense when they melt. When the Earth's crust becomes very hot the rocks are molten or semi-molten. As they are less dense when they melt they tend to move upwards to the surface. The melting of the rocks is a slow process due to the minerals that form the rocks which have different compositions.

cannabis

explanation:

(assuming this is the us) google it. law states you can't have weed.

the correct answer is modern american cars are not available due to trade restrictions.

trade between cuba and the united states have serious restrictions. the u.s. imposed an economic embargo on cuba, that among other things means that modern american cars are not available due to trade restrictions.

in response to some governmental actions of the authorities from cuba, president john f. kennedy proclaimed an embargo on trade between both countries in february 1962. the trade embargo remains active until this day and was implemented directly by the departments of commerce and the department of treasury.

in president trump’s administration, there is a national security presidential memorandum that "strengthens the policy of the u. s.", affecting trade with cuba.