The correct answer is the arterial blood carbon oxide level.
Arterial blood test measures oxygen and carbon dioxide levels in the blood. It also measures the body's acid-base level, which is normally balanced when an individual is healthy. The normal range for carbon dioxide is 23 to 29 mEq/L.
1. outer covering - none of the other answers can occur due to the absorbed solutions inability to reach the centre of the organism, smaller cells in greater numbers are more efficient as they can group together yet all absorb the right amounts of nutrients for its need. multi cellular organisms, such as humans can have the other answers in them as cells group together to make skin, muscles and organs. it also gives the organism to grow larger.
2. bacteria are single celled. bacteria reproduce through mitosis (cell division). bacteria break down decaying matter to obtain energy. every organism requires energy to live. Bacteria can move in order to reach their nutrient source.