Why are bacteria required in the nitrogen cycle?
A. Nitrogen needs to be fixed before it is used by plants.
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B. The xylem in plants cannot function without bacteria.
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C. Plant DNA can only be transmitted by bacteria.
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D. Plants need to pull nitrogen directly from the air.

Match the acid base pairs by arranging the acid name with the conjugate base formula. hydrogen carbonate hydrogen phosphate carbonic acid read water sulfuric acid phosphoric acid a. co32- b. hso4- c. hco3- d. po43- e. h2po4- f. oh-

Identify and describe the three ways that mutations affect organisms.

6. using 3 – 4 sentences explain (in your own words) why water expands when it freezes? 7. using your knowledge of colligative properties explain whether sodium chloride or calcium chloride would be a more effective substance to melt the ice on a slick sidewalk. use 3 – 4 sentences in your explanation.