Q: By what process does oxygen enter the pores of flatworms? Choices: - absorption - filtration - permeation - diffusion A:
diffusion
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Q: The passing of traits from parents to offspring is done through what? Choices: - sperm - egg - blood - dna A:
dna
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Q: What is studied to understand gene expression patterns in cells? Choices: - dna - protein - mutations - rna A:
rna
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Q: The total number of protons and neutorns in an atom is called what? Choices: - atom number - volume number - formation number - mass number A:
mass number
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