The center of the dna molecule, the rungs of the ladder, are composed of
a. phosphates only.
b. nitrogenous bases only.
c. phosphates and sugars.
d. nitrogenous bases and sugars.

The health, management and conservation of biodiversity, is a challenge facing ecosystems worldwide. the major factors that affect the health and function of the great barrier reef are climate change and pollution. which question investigates the effects of a biotic factor on the reef ecosystem?

Karen is a forensic scientist whose purpose is to identify and evaluate physical evidence. which of the following tasks does she perform? a. reporting results of scientific analysis b. interviewing suspects c. questioning witnesses d. preparing victims for burial

Which best describes how sediment forms? loose material is cemented by pressure. erosion breaks down rock and other material. molten rock cools above earth's surface. chemical changes cause sediment to compact together.