Purple sulfur bacteria and filamentous sulfur-oxidizers both a. accumulate sulfur as intracellular granules. b. fix nitrogen. c. produce oxygen from carbon dioxide. d. use gliding motility.

Option A, accumulate sulfur as intracellular granules.

Explanation:

Purple sulfur bacteria  belong to the group of Proteobacteria. These probacterias are  anaerobic  in nature and yet are able to photosynthesise. They are usually found in  water environments  such as hot springs, stagnant water etc. They use sulphur (either in the form of sulfide, or thiosulfate) as an electron donor in their photosynthetic activity to oxidise sulfur thereby producing granules of elemental sulfur.

while filamentous sulfur oxidizers use nitrate instead of oxygen to oxidize sulfide thereby producing granules.

Hence, option A is correct.

relative humidity, temperature and dew point -- are bound together in the mathematical relationship below. relative humidity changes when temperatures change. because warm air can hold more water vapor than cool air, relative humidity falls when the temperature rises if no moisture is added to the air. so i would say a