Rock is formed when debris is buried, compressed and cemented together.
a. sedimentary
b. magma
c. metamorphic
d. igneous

Which of the following is one of the four conditions necessary for natural selection to occur in a population? fewer organisms are born than the habitat can support mutation does not occur organisms have identical characteristics variation is inherited

Many organs are involved in the processes of keeping the blood and the body clean. when poisonous or harmful substances are in the blood, they are absorbed by the and released in a less harmful form. when wastes are present in the blood, they are filtered out and removed from the body by the

Temperatures in ponds and lakes vary by season. select the best answer from the choices provided t f