A biology class wanted to study the effect of different materials on the melting rate of ice. They placed pieces of ice, each with a mass of 10g, onto trays. Group 1 was covered in plastic, group 2 was covered in paper, group 3 was covered in aluminum, and group 4 remained uncovered.

Each piece of ice was allowed to melt for 15 minutes. Then final mass of the ice, minus the melted water, was recorded at the end of the experiment.

Which of the following is the control group in this experiment?

A. group 3

B. group 1

C. group 2

D. group 4

What is the primary function of the nervous system?

When making her coffee, mrs. jenkins likes to stir in some cream and sugar to give it a pleasant flavor. the ingredients, when combined like this, form a

Our planet has experienced five major extinctions in the four billion year history of life. the first, 450 million years ago, occurred shortly after the evolution of the first land-based plants and 100 million years after the cambrian explosion. the second extinction occurred 350 million years ago, causing the formation of coal forests. next earth experienced two mass extinctions during the triassic period, between 250 and 200 million years ago. the fifth mass extinction occurred 65 million years ago, ending the reptilian dominance of the earth. according to richard leakey, the sixth mass extinction is happening right now. leakey suggests that we, the human race, are the cause. each year, at our hand, approximately 50,000 species vanish from earth. he believes that man is destroying earth at a rate comparable with the impact of a giant asteroid. leakey's statistics indicate that 50% of earth's species will become extinct within the next 100 years assuming leakey's hypothesis of a sixth mass extinction to be true, how will we expect the model to change? a) a sharp spike in the graph approximately 100 million years from now b) a dip in the graph, followed by a sharp spike about 100 million years from now c) a sharp spike in the graph immediately following the "0" location of the x axis d) a plateau following the "0" mark on the x axis, followed by a gradual rise to a new peak