Answer:
Transcription factors
Explanation:
They are part of the cell's core transcription toolkit, needed for the transcription of any gene. RNA polymerase binds to a promoter with help from a set of proteins called general transcription factors.
The keystone species is the one at the bottom of the pyramid, if we look at it like a pyramid. If the grass dies, then the deer cannot get food and die, and the predator cannot eat and dies, and the whole ecosystem can fall apart.
When h forms a bond with h2o to form hydronium ion, h3o , this bond is called a coordinate covalent bond.