Nitrogen is fixed or combined, in nature as nitric oxide by lightning and ultraviolet rays, but more significant amounts of nitrogen are fixed as ammonia, nitrites, and nitrates by soil microorganisms.
Invertebrates have no spine, and they often don't have nearly as many organs as vertebrates. Overall, they are much simpler organisms.
Answer:
The rock cycle is a constant transformation of rocks between the three rock types of igneous, sedimentary, and metamorphic. If the sediments are buried behind other layers of sediment, they can lithify and form sedimentary rock. When rocks melt, magma is formed. Rocks form deep below the Earth, move and sometimes change, rise to the surface, and eventually return to their original location.
Answer:
heterotrophs survive through respiration, using oxygen and an energy source (carbohydrates, fats or protein) to produce ATP, which powers cells. They depend on other organisms for food and oxygen. Photosynthesis benefits heterotrophs in several different ways. First, "photosynthesis consumes carbon dioxide (a waste product of respiration) and produces oxygen (necessary for respiration)." Heterotrophs therefore depend on photosynthesis as a source of oxygen. In addition, "photosynthesis sustains the organisms that heterotrophs consume in order to stay alive. Even if a heterotroph is strictly carnivorous and does not eat plants, it must eat animals that eat plants to survive."
Answer:
D&B
Explanation:
Each chromosome contains a single double-stranded piece of DNA
one chromosome contains thousands of genes
