Which of the following would be one way a farmer could increase the amount of available nitrogen in his fields without adding a synthetic fertilizer?
grow a legume crop to support the development of root nodules.
flush the field with water.
burn unwanted plants on the field.
add nitrogen gas to the fields.

Nucleic acids offer variability because they contain alternate forms of genes called .

Define the apical impulse and describe its normal location, size, and duration. which abnormal conditions may affect the location of the apical impulse? explain the mechanism producing normal first and second heart sounds. describe the effect of respiration on the heart sounds. describe the characteristics of the first heart sound and its intensity at the apex of the heart and at the base. describe the characteristics of the second heart sound and its intensity at the apex of the heart and at the base.

What are positive impacts of algae? how is it used?