1. Nutrients move through an ecosystem in :
A) biogeochemical cycles
B) water cycles
C) energy pyramids
D) ecological pyramids
2. In the nitrogen cycle, bacteria that live on the roots of plants:
A) break down nitrogen compounds into nitrogen gas.
B) denitrify nitrogen compounds
C) change nitrogen gas into plant proteins
D) change nitrogen gas into ammonia
3. Which biogeochemical cycle does NOT involve a stage where the chemical enters the atmosphere?
A) the water cycle
B) the carbon cycle
C) the nitrogen cycle
D) the phosphorus cycle
4. When an ecosystem is limited by a single nutrient that either is scarce or cycles very slowly, this substance is called a (an):
A) nitrogen compound
B) organic phosphate
C) biogeochemical cycle
D) limiting nutrient
A) biogeochemical cycles
B) water cycles
C) energy pyramids
D) ecological pyramids
2. In the nitrogen cycle, bacteria that live on the roots of plants:
A) break down nitrogen compounds into nitrogen gas.
B) denitrify nitrogen compounds
C) change nitrogen gas into plant proteins
D) change nitrogen gas into ammonia
3. Which biogeochemical cycle does NOT involve a stage where the chemical enters the atmosphere?
A) the water cycle
B) the carbon cycle
C) the nitrogen cycle
D) the phosphorus cycle
4. When an ecosystem is limited by a single nutrient that either is scarce or cycles very slowly, this substance is called a (an):
A) nitrogen compound
B) organic phosphate
C) biogeochemical cycle
D) limiting nutrient