Answer:
The main difference between sieve tubes and companion cells is that sieve tubes are the long, narrow, pointed tubes present in the phloem of angiosperms whereas companion cells are attached to the sieve tubes, regulating the activity of sieve tubes.
The correct answer for this question is "Epiglottis". The Epiglottis is responsible for cutting off the passage way to the airway while swallowing/eating food to prevent the food from being inhaled by the body.The Epiglottis has a leaf-like shape structure with a cartilage that covers the passage way into the air ways of the body.
concentration of the enzyme, concentration of the substrate, and temperature. However there are more than three. A lock and key analogy is used when explaining the specific action of an enzyme with a single substrate.
Well, MOST pathogenic bacteria is harmless, but SOME could cause death, like tuberculosis, but just in case you would want to mark the answer as, "True".
I hope I helped! =D
An atom that has gained or lost electrons is called an ion
