Answer:
B: volcanic activity
D: fossil fuel consumption
Explanation:
Fossil fuel consumption and volcanic activity are the two factors that has a great influenced on the global temperatures. Fossil fuel consumption is a human activity and volcanic activity both releases carbondioxide gas while burning. This carbondioxide gas is a greenhouse gas which block the reflected solar radiation and leads to increase in the surface temperature of the earth.
Perhaps the answer is "physical characteristics". I am simply making an educated guess, however I do know early philosophers classified organisms into two groups, Plants and Animals, and identified them based on physical characteristics.
B. The flower color in a population changes over time.
Remember that a controlled variable is a variable that stays the same thoughout the experiment.
it wouldn't be a. because two different wires were used
the final length of the wax would be your dependent variable, so it wouldn't be c.
the thermal conductivity is the independent variable so it isn't d.
the original length of the wax was the same for both.
So B is your answer.
