Question

1.Plants fix nitrogen by

A. respiration

B. photosynthesis

C. osmosis

D. bacteria

2. True or False:

About 1 in 5 solar systems outside of our solar system has an Earth-sized planet that could support life as we know it.

3. True or False:

The mind is altered by each new event it encounters.

4. Endocrine changes as a result of aging

A. differ between genders

B. are regulated by a central pacemaker in the hypothalamus

C. cause hormonal alterations

D. all of the above

Answer 1

Ans 1) The correct answer is "D" i.e Bacteria

The rest of the options are straightaway eliminated because biological nitrogen fixation only occurs by the bacteria like Rhizobium leguminosarum,azotobacter,etc.These bacteria can live inside the root nodules of the leguminous plants and fix the nitrogen.Nitrogen fixation is an anaerobic process because nitrogenase complex is very sensitive to oxygen and can get inactivated irreversibly by oxygen.So,rhizobium can produce leghemoglobin to maintain anaerobic conditions in root nodules for nitrogen fixation)