Which statement best describes the role of plate tectonics in changes that occur on Earth? A: Convection currents in the mantle cause mountain ranges to slowly collapse over time.
B: The subduction of oceanic crust cools the mantle and prevents volcanic eruptions.
C: The movement of plates builds pressure that is released during an earthquake.
D: Seafloor spreading causes ocean basins to get smaller and shallower over time.

the answer is A i learned this in class and i had the exact same question

"you start with 15.67 g mgco3-xh2o, when heated and all the water is removed, you are left with 7.58 g mgco3 only.

therefore, you had 15.67 - 7.58 = 8.09g h2o  

moles of each :

7.58g mgco3 = ? moles = 7.58g / 83.4g/mole = 0.09moles  

8 09g h2o = ? moles = 8.09g / 18g/mole = 0.44moles  

molar ratio between the two by dividing both numbers by the smallest number :

0.09 / 0.09 = 1  

0.44 / 0.09 = 4.8  

mgco3-5h2o"

air

in a tire you fill a tire with air

then a couple days later you check the air pressure in the tire

hope this mark me brainliest