Answer:Hydrogen
Explanation:
The pH scale is a measurement system that indicates the concentration of HYDROGEN IONS in a solution. The pH scale ranges from zero to 14. A pH that is less than 7 is considered to be acidic while a pH that is more than 7 is considered to be basic.
I think the correct answer from the choices listed above is option A. Tuber is considered as a modified stem. These type of stems carry out special functions that are important for the plant to survive. Tubers serves as a food reserve and bearing buds wherein new plants can grow.