The verb form of hard is harden. As in "to harden something".
thousands of years
To write 900 thousands in standard form, you multiply 900 by 1,000. This gives you 900,000. Therefore, 900 thousands in standard form is 900,000.
12,000 = twelve thousands
139 thousands in decimal form is 139,000139 thousandths in decimal form is 0.139
The verb form of hard is harden. As in "to harden something".
thousands of years
The verb form of hard is harden. As in "to harden something".
Fossil fuels, such as coal, oil, and natural gas, were formed over thousands of years from the remains of plants and other organisms. When these fossil fuels are burned, they release stored energy in the form of heat, which is used for electricity generation, transportation, and heating.
Yes
by erosion but it takes thousands of years to form.
When plants die on land, they can form peat, which can then transform into coal over millions of years due to heat and pressure. Coal is a fossil fuel that is commonly formed from the remains of terrestrial plants.
Coal takes millions of years to form from the pressure of dead plants and trees in swamps.
A sedimentary rock takes thousands to million of years to form because it is formed from lava (or magma). After thousands and millions of years, allowing the rock to cool, forms a rock shape, which we call a sedimentary rock. Please don't copy and paste this answer to present it as your own. Your Welcome!
Erosion, it happened probably over thousands of years
That's extremely variable and specific to each cave, but you have to think in tens or hundreds of thousands of years.
igneous rock