Answer:
B. The membrane lets certain substances move across it freely, while others must move through a “gate”.
Explanation:
Selective permeability is a property of cellular membranes that only allows certain molecules to enter or exit the cell. This is important for the cell to maintain its internal order irrespective of the changes to the environment. For example, water, ions, glucose and carbon dioxide may need to be imported or exported from the cell depending on its metabolic activity. Similarly, signaling molecules may need to enter the cell and proteins may need to be released into the extracellular matrix. The presence of a selectively permeable membrane allows the cell to exercise control over the quantum, timing and rate of movement of these molecules.
The order of flow of oxygen within the human body may be described simply. Oxygen first is inhaled through the nasal cavity and then passes through the trachea, through the bronchi and into the lungs. In the lungs, the oxygen is passed into the blood stream through the alveoli and then is carried to the heart. The heart pumps this oxygenated blood throughout the body, primarily to organs and muscle cells, where it is consumed in respiration and is converted to carbon dioxide and excreted.
Answer:
The waste products are Carbon Dioxide and Water.
Explanation:
Answer: A) Light
Explanation:
Hey!! It's me again because why not!!
