Nitrogen fixation A) is carried out by certain types of bacteria. B) cannot be done by plants. C) changes nitrogen to a form called nitrates. D) all of the above

Deer cave cannot support photosynthesis is as not enough sunlight is present. in spite of this, it still has a complex food chain. what is the energy foundation of this food chain?

Aperson with age is more likely to catch diseases that healthy people usually don’t catch. what are these infections called?

During the winter, this species of fox has white fur, but in the summer, it has brown fur. what environmental change may have lead to this fox's fur color? snow cover increase in sun's brightness volcanic eruption global warming