During the prophase the nucleoli in the nucleus disappear. The chromatin fibers become tightly ccoiled and condense into chromosomes. Chromosomes line up in pairs and are joined at the centromere. In the cytoplasm, the spindle fibers begin to formand are made of microtubules.
Early pre-cambrian period the atmosphere consisted only of nitrogen and carbon dioxide without oxygen.
<span>A Prokaryotic cell does not contain a nucleus. It only contains one chromosome and is a single-celled organism. It was the only form of life on earth for millions of years. Examples of a Prokaryotic cell are the different types of bacteria present today.
</span><span>Autotrophs obtain energy by the process of photosynthesis. Any living organism need energy to survive and autotrophs are no different. Two types of autotrophs are present and they are Photoautotrophs and Chemoautotrophs. The Photoautotrophs rely on the energy produced during the process of photosynthesis and the Chemoautotrophs get their energy from most of the inorganic substances. Phtoautotrophs actually get their energy from the sunlight and then convert it into reusable form. In case of Chemoautotrophs ammonia is an important source of energy for them.</span>
During normal breathing, the brain is stimulated to breath with increasing acidity as a result of CO2 concentration from basic metabolic processes. The brain is quite selfish and only really wants to maintain it's pH which should be at a range of 7.3-7.45, and will not tolerate any decrease.
In patients who have a chronic respiratory disorder with things like COPD. The brain has become accustomed to excessive acidic content, and is now stimulated by the Hypoxic drive or by low oxygen content.
A system of winds rotating inward to an area of low atmospheric pressure, with a counterclockwise (northern hemisphere) or clockwise (southern hemisphere) circulation; a depression.
