External respiration is the process of taking oxygen into and expelling carbon dioxide from the body. External respiration is essential for life as it supplies oxygen to extract energy from food via internal or cellular respiration. Additionally, it removes carbon dioxide, which is a waste product of respiration.
The nucleus is a membrane bound structure that contains the cell's hereditary information and controls the cell's growth and reproduction.It is commonly the most prominent organelle in the cell. The nucleus is surrounded by a structure called the nuclear envelope.This membrane separates the contents of the nucleus from the cytoplasm. The cell's chromosomes are also housed within the nucleus.he nucleus is surrounded by a structure called the nuclear envelope. This membrane separates the contents of the nucleus from the cytoplasm. The cell's chromosomes are also housed within the nucleus.
Report Abuse. a nucleus (nucleii refers to more than one nucleus, it is the plural form of the word nucleus) is a core, the central and generally key or most important thing to the total structure. A nucleus, when discussing cells, is the area of the cell where genetic material resides. It has its own structural border (a semi-permeable wall separating it from the main cell mass). You must know what a cell nucleus is without needing further detail. It is a fairly basic term to cell biology.