Answer:
Tell the younger student that organs are singular objects and systems are a group of organs that work together to perform certain jobs.
Explanation:
Organs are singular units that play a part of human survival. (Ex. the heart cleans the blood and pushes through your veins)
Systems are a group of the singular units that work together to perform a certain function.
(Ex. Lungs, heart, veins and arteries make up the circulatory system which transports oxygen, blood, and nutrients through out your body)
Teperature
Ph level
Substrate concentration
Not sure if these are physical but hope it helped.
Yeast has many comercial uses in the production of breads, fuel, sodas, and wine.
