<span> RNA polymerase is commonly know as DNA-dependent RNA polymerase. It catalyzes the transcription of DNA to synthesize precursors of mRNA and most snRNA and microRNA. It is found in the core of eukaryotic cells. One of which combined rRNA in the nucleolus while the rest of the chemical blends other RNA in the nucleoplasm, some portion of the core yet outside the nucleolus.</span>
Answer: Option B
Explanation: The first line of defense acts a barrier and does not allows the foreign materials to enter inside the body. It includes chemical and physical barriers that are always ready to protect the body from infection.
Example: Skin and mucous membrane.
Skin is largest organ and it acts as a barrier between pathogens and human body. It acts a waterproof material and the pathogens cannot get inside through skin unless the skin is broken.
Mucous membranes also acts as first line of defense and breaks the cell wall of many bacteria entering through the openings of the body.
So, skin and mucous membrane are the first line of defense.
Answer:
d . different population of the same species physically separated from each other forming new species.