Which ecosystem of the following situations contributes to the sustainability of an ecosystem
A. Increases biodiversity
B. Decrease in bio diversity
C. Excision of a population from the ecosystem
D. Removal of many populations of an organism

Sydney drew a flow chart to illustrate the nitrogen cycle.which labels best complete the flow chart? x: producers undergo photosynthesis.y: nitrogen compounds are released into the air.x: nitrogen compounds are released into the air.y: producers undergo photosynthesis.x: free nitrogen is in the atmosphere.y: producers absorb nitrogen compounds through their roots.x: producers absorb nitrogen compounds through their roots.y: free nitrogen is in the atmosphere.

Explain how ancient whale fossils found in eqypt are believed to support the theory of evolution.

Which of these substances does not protect against invaders in the nonspecific immune response? a. saliva b. mucus c. tears d. urine