What type of rock would be found by the mouth of a river

Sedimentary rock would be found at the mouth of a river i hope this helps you

It's always a sedimentary rock Remember that,hope it helps

The peak above is part of the  sierra madre occidentals ,  a chain of volcanic mountains that runs through the middle of central america. 

The scientist can conclude that there is a decrease in the natural resources due to human activities. because of innovation and modernization of the environment, then there goes pollution and other bad effects that destroys the natural resources.