Answer: A
Explanation: Cancer is unchecked cell growth. Mutations in genes can cause cancer by accelerating cell division rates or inhibiting normal controls on the system, such as cell cycle arrest or programmed cell death. As a mass of cancerous cells grows, it can develop into a tumor.
It's letter A - Obligate anaerobe.
<em>Obligate anaerobes</em> are microorganisms killed by normal atmospheric concentrations of oxygen. A <em>facultative anaerobe</em> prefers to produce energy in the presence of oxygen but can survive without it. <span>A <em>photoautotroph </em>is an organism that converts light energy into chemical energy. </span><span>Prokaryotes may perform </span>aerobic<span> (oxygen-requiring) or </span>anaerobic<span> (non-oxygen-based) metabolism and some can switch between these modes. Since we're talking about an environment without oxygen and dies when exposed to oxygen, the preferable answer is A.</span>
The plasma membrane of axon is called axolemma. The potassium and sodium leak channels leak the sodium and potassium ions inside the cell respectively. The leak channels provide the constant movement of ions across the membrane. Potassium and sodium ions are positively charged, thus entry of positively charged ions inside the cell makes the cell more positively charged than the environment outside the cell. The environment outside the cell becomes more negatively charged. This leads in the negative membrane potential of axolemma.
