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. what are the independent variables& a dependent variables?

What we want to measure is the taste of coffee.

The following were kept constant during the experimental investigation:
The type of coffee,
The type of percolator,
The same amount and type of water,
The same perking time,
The same electrical sources.

Because these items were kept constant, they are not expected to influence the outcome of the experimental investigation.

Define:
y = the metric used to measure the taste of coffee
x = amount of coffee grounds used for the taste experiment.

Therefore the relationship that arises from the experiment is
y = y(x).

Because x is controllable and is varied during the experiment, it is the independent variable.
Because the measured value of y depends on x, therefore y is the dependent variable.

The taste of coffee is the dependent variable.
The amount of coffee grounds used is the independent variable.

Alpha particles have positive charge, beta particles have negative charge, and answer 4 just doesn’t make sense. thus, you are left with only one possible answer.