Small stretches of DNA are called genes. Genes carry the code for proteins. How many nucleotides in a gene must be read to add a single amino acid to a protein? *​

4. how does a phospholipid behave in water? the phosphate head does not mix with water; the fatty acid tails do. the phosphate head and the fatty acid tails mix with water. the phosphate head and the fatty acid tails do not mix with water. the phosphate head mixes with water; the fatty acid tails do not.

The circles, or orbits, for electrons are called energy levels. each level can hold only a certain number of electrons. add electrons to each level until you can't add any more. how many electrons can each level hold?

Which ideas did your answer contain? check all that apply. no food for organisms no oxygen in the atmosphere no trees or flowering plants no products based on trees or plants (building materials, medicines, fuels, fibers) no fossil fuels