Answer:
In a research there are two variables independent and dependent variable. independent variable is defined as the variable which is controlled and changed in a scientific experiment and evaluate the effects on the dependent variable while the variable which are tested and measured in experiment are called dependent variable.
When antibiotic is sprayed at one side of the petri dish, the bacterial growth on that side will eventually decrease in comparison to other side.
So, the independent variable in this experiment will be antibiotic because it is used to understand the growth of bacteria by decreasing their numbers and the dependent variable in this experiment will be bacteria as they vary according to the change in independent variable that is antibiotic.
The answer is most likely "vascular system". Xylem tissue is a part of a plant's vascular system. Which is mostly responsiple for transportation (of water, food etc.) in a plant. The vascular system of plants is made of two tissues. One is Xylem and the other is Phloem. Phloem transports food from leaves to all other parts of the plant. And Xylem transports water and minerals (which are dissolved in the water) to the leaves.
So if you remove the <u>Xylem</u> tissue from a plant, its vascular system will be affected.