You catch, tag, and release 50 fish back into a pond. Then, you catch 25 more fish, 5 of which are tagged. What is the best estimate of the number of fish in the pond?

Crust,mantle,core,earth

Its the second one nonmetals are moldable and easily shaped 

It is a mixture. simply put, a compound must be pure, that is, of only one chemical structure and composition. a mixture is made of different chemical substances (i.e. elements, molecules, compounds) that are not chemically bonded to each other, but instead physically grouped together, as in the case of gasoline (a homogeneous solution).