Why is the weather so hard to predict?

Which is the layer underground where all empty spaces are filled with a combination of air and water ?

Use the drop-down menus to answer each question. which runner finished the 100 m race in the least amount of time? which runner stopped running for a few seconds during the race? at what distance did anastasia overtake chloe in the race?

One similarity and one difference between an element and a mixture of elements