What is missing in my diet to cause receding gums and thin fingernails?

Which class of molecules contains the amino group, nh2 (a) sugars (b) water (c) proteins (d) hydrocarbons

Many kangaroo rats live in the sonoran desert of the southwestern united states. they have a variety of adaptations for living in the desert. under which circumstance would the kangaroo rats of the sonoran desert be most likely to develop new adaptations by natural selection?

What advantage does a crop that undergoes vegetative reproduction have over plants that start from the seed? 1points a they store nutrients. b they can travel farther. c they experience more genetic variation. d they only occur in high-resource environments.