Biologists use ball-and-stick models to study complex molecules by representing atoms with balls and bonds with sticks. dna is a biological molecule that contains millions of atoms. what is a limitation of using a ball-and-stick model for dna?
some kinds of atoms that are found in dna must be left out of the models.
dna has so many atoms that the size and cost of a model could be too great.
it is impossible to distinguish different kinds of atoms with models.
the chemical bonds between the atoms in dna must be part of the models.

According to the theory of punctuated equilibrium, at what rate does speciation occur? species change depending on the rate of natural selection. after periods of stasis, new species evolve relatively rapidly. species change slowly and eventually form new species. some species change quickly and others change slowly to balance the overall rate.

Researchers randomly divide participants into groups. each group takes a different amount of omega-3 fatty acid supplements daily for a month. one group receives a placebo. the researchers measure the impact on cholesterol levels in the blood. what is the purpose of random assignment in this experiment? a, to produce treatment groups with similar characteristics b, to ensure that all people with high cholesterol have an equal chance of being selected for the study c, to increase the accuracy of the research results and prevent skewness in the data

Asmall population of chimpanzees lives in a habitat thant undergoes no change for a long period of time. how will genetic drift affect this population