Complete the sentences to describe the structure of DNA. The shape of the DNA molecule is called a double . The backbone of DNA is made of molecules and phosphate molecules. The "rungs" of DNA are made of .

Which continents lie only in the northern hemisphere

What can happen to solar radiation when it enters earth’s atmosphere? check all that apply. it is absorbed by earth. it is reflected by clouds. it is reflected by glacial ice. it is condensed into visible light. it is amplified by water molecules.

Technology has affected regional settlement patterns in what ways? choose all that apply. climatic improvement strategies have improved crop productivity. mechanized agricultural methods have improved agricultural productivity. participation in the global economy has increased urbanization. population shifts from urban to rural areas has increased as a result of petroleum production. settlement areas have increased as a result of improved water storage and delivery systems.