The smallest of the single-celled organisms that assist with decomposition in the soil are most likely to have which of the following characteristics?
a. a different form of dna containing uracil instead of thymineb. chitin or cellulose in their cell wallsc. branching, ether-linked hydrocarbons in their cell membranes d. a special form of rna polymerase unique to their domain

The correct answer is option C, Branching ether -linked hydrocarbons in their cell membranes

Reason -

The cell wall of the bacteria includes branched chain alcohols, lipids, ether and phytanales which are connected to glycerol. These chemicals prevent the bacteria from extreme weather conditions and temperatures. It also reduces the fluidity of cell membrane. Due its distinctive cell wall , the bacteria is able to survive in harsh conditions while degrading dead organic matter.  

"A special form of RNA polymerase unique to their domain"

Explanation: This is correct becuase I just took the test. I had it narrowed between, Branching,

1. ether-linked hydrocarbons in their cell membranes

2. A special form of RNA polymerase unique to their domain

and I chose #2 and it was right.