Which kind of organism is a autotroph

Algae    , which live in water and whose larger forms are known as seaweed, is autotrophic. Phytoplankton, tiny organisms that live in the ocean, are autotrophs. Some types of bacteria are autotrophs. Most autotrophs use a process called photosynthesis to make their food.

Rna polymeras should attache to the promoter.

Where are they though?