How do we know the composition of the upper mantle?
A. Some caves extend into the mantle
B. Meteorites are similar to the mantle
C. Samples of mantle rock have been
analyzed by scientists
D. All of the above

Environmental differences within ecosystems are generally caused by

Which statements describe resources? one of the factors people use when deciding where they will live is the availability of resources. renewable resources have little value for people. resources are unevenly distributed throughout the world. energy is the world resource which has the highest use. the use of nonrenewable resources has decreased in recent history. the use of resources is evenly distributed throughout the world. the world's oil supply will last for the next forty years if its use continues as expected.

Select the true statements about eubacteria. most live as decomposers and heterotrophs. most only thrive in a narrow range of environments. certain eubacteria are responsible for food poisoning. eubacteria thrive in extreme environments.