6. an experiment was performed to determine how the amount of coffee grounds could
affect the taste of coffee. the same kind of coffee, the same percolator, the same
amount and type of water, the same perking time, and the same electrical sources were
used.
independent variable:
dependent variable:
controlled variables (3):

The independent variable in the experiment is amount of coffee grounds. The dependent variable is the taste of coffee. The control variables are; kind of coffee, type of water and perking time.

The independent variable in an experiment is the variable that is being manipulated in the experiment. Changes in the independent variable results in changes in the dependent variable. The control variables are those variables that must be held constant in order to obtain meaningful results.

In this case, the independent variable is amount of coffee grounds. Its effect on the dependent variable which is  taste of coffee was studied in the experiment.

Controlled variables such as kind of coffee, type of water and perking time were all held constant.

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explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.  

they vary. it used to be meat, grain, bread, candy, beverages, donuts, and fruits/vegetables. now they added exercise in.