Mrs. Kirby, 58, is a moderately active woman. She works in the garden almost daily, occasionally walks with her friends, and babysits her three very active young grandchildren every weekend. She eats a fairly standard diet every day: she has cereal with milk and coffee for breakfast, some kind of salad for lunch, and a piece of meat or fish with a healthy helping of veggies for dinner. She usually skips desserts or has just a couple of strawberries. When asked to look at the food labels and calculate her intake of carbohydrates, fats, and proteins in grams over the entire day, on an average day, she came up with the following numbers: Carbohydrates: 243 g Fats: 41 g Proteins: 63 g

Viruses use the host's machinery to make copies of themselves. however, some human viruses require a type of replication that humans do not normally have. for example, humans normally do not have the ability to convert rna into dna. how can these types of viruses infect humans, when human cells cannot perform a particular role that the virus requires? a) the virus causes mutations in the human cells, resulting in the formation of new enzymes that are capable of performing these roles.b) the viral genome codes for specialized enzymes not in the host.c) the virus infects only those cells and species that can perform all the replication roles necessary.d) viruses can stay in a quiescent state until the host cell evolves this ability.

Aresearcher lyses a cell that contains nucleic acid molecules and capsomeres of tobacco mosaic virus (tmv). the cell contents are left in a covered test tube overnight. the next day this mixture is sprayed on tobacco plants. we expect that the plants would ) develop some but not all of the symptoms of the tmv infectionb) develop the typical symptoms of tmv infectionc) not show any disease symptomsd) become infected, but the sap from these plants would be unable to infect other plants

Why do you need two different circuits of blood vessels in your body?