Sulfur dioxide<span> and </span>nitrogen oxide mix <span>with the water molecules in the atmosphere to produce acidic rain </span>
Transcription factors are necessary for an initiation of transcription at a regulated gene but not sufficient.
Transcription is the first step of gene expression in which DNA molecule is copied (transcribed) into RNA (mRNA) by RNA polymerase. The process of transcription is divided into three phases:
1. Initiation
• RNA polymerase with transcriptional factors bind to gene promoter Transcription factors can enhance the interaction between RNA polymerase and a DNA sequence- promoter, encouraging the expression of the gene. Such transcription factors are called activators. Otherwise, when the gene expression is inhibited, factors are called repressors and they bind to sequence –operator.
• RNA polymerase unwinds DNA double helix (transcription bubble is formed)
2. Elongation
• RNA polymerases adds nucleotides complementary to DNA
3. Termination
• RNA polymerase gets to stop codon (transcribes a sequence of DNA known as a terminator)
• Formed complementary RNA strand is released from DNA-RNA complex
Answer:
All mammals, like dogs, cats, and humans; reptiles, amphibians, fish, birds, and even insects.
Explanation:
All mammals, like dogs, cats, and humans; reptiles, amphibians, fish, birds, and even insects are the animals that have a complete tube-like gut with two openings. A system having a tube with two openings i.e. mouth and an anus is called tubular system. In this tubular system, the animals eat with one opening and the other opening is used for excretion of waste and nitrogenous materials from the body so that's why most of the animals have two openings.
