The Nitrogen Cycle
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· 1.Which are the two main parts of the natural nitrogen cycle?
o A) synthesis and decay
o B) legumes and bacteria
o C) manure and rotting tissue
o D) combining and converting
o Explanation: Wrong
· 2.Which of the following need nitrogen to survive?
o A) fish
o B) plants
o C) humans
o D) all of the above
o Explanation: Wrong
· 3.Some animals get the nitrogen they need from the _____.
o A) soil
o B) plants they eat
o C) air they breathe
o D) water they drink
o Explanation: Wrong
· 4.Most plants CANNOT use nitrogen _____.
o A) fixed by bacteria
o B) in the pure gas form
o C) in the soil where they grow
o D) dissolved in the water where they grow
o Explanation: Wrong
· 5.Which thing, in addition to nitrogen-fixing bacteria, changes nitrogen into a form that is easier for plants to absorb?
o A) corn
o B) animals
o C) lightning
o D) plant stems
o Explanation: Wrong
· 6.Where do the nitrogen-fixing bacteria that have a symbiotic relationship with legumes live?
o A) They live freely in the soil.
o B) They live in the legumes’ leaves.
o C) They live in nodules on the legumes’ roots.
o D) They live in the carbohydrates produced by the legumes.
o Explanation: Wrong
· 7.What happens when there is excess nitrogen in lakes?
o A) Fish grow fast and eat up all the available food.
o B) Water plants grow fast and rob the water of its dissolved oxygen.
o C) Other bacteria kill off the nitrogen-fixing bacteria present in the water.
o D) Water plants die because they can’t use the form of nitrogen found in the water.
o Explanation: Wrong
· 8.When nitrogen pollution in the air combines with water in the atmosphere, it often returns to the earth as _____.
o A) fertilizer
o B) acid precipitation
o C) excess nitrogen gas
o D) denitrifying bacteria