N the Watson-Crick model of DNA, the two strands of the double helix are united by hydrogen bonds between a.
nitrogenous bases

b.
phosphate groups

c.
nitrogen atoms

d.
sugar molecules

Christie's doctor recommends that she eat 40 grams of protein a day. she's already consumed 50% of her protein recommendation for the day. how many servings of the given snack should christie have to meet her daily protein recommendation?

The diagram illustrates the activity of vesicles during a cellular process.

The concept of keystone species is controversial among ecologists because most organisms are highly interdependent. if each of the trophic levels is dependant on all others how can we say one is most important