The most common elements in the Earth’s crust are rarely found on their own. They are usually found combined. Suggest why this is.

The most common element throughout the Earth’s crust that are rarely found on their own will be "Astatine".

Thus the above answer is correct.

Learn more about Astatine here:

link

Because there are other elements that get in touch with it. And over time with, evolution, erosion and temperature their particles tend to mix. So what once was very common became mixed over time.

the skeletons of most mammals reach a certain size and then stop growing. however, many animals, including some mammals, keep growing throughout their lives. kangaroos, for example, just keep growing and growing until they die. also, the longer an animal lives the greater the chance it might catch some deadly disease.

we're given that v₀ = 0 and a = 5.4 m/s². therefore, since v = at + v₀ for constant acceleration the equation for velocity is

after 28s,

m/s

which i would round to 150 m/s as my final answer