Many lakes in the United States are suffering from periodic algae blooms, which can be thought of as an infection of the lake. Although the algae are naturally-occurring in the lake, when adjacent farm fields are over-fertilized with diammonium phosphate, the run-off deposits these nutrients in the lake, allowing the algae to grow without limit. Which of the following statements is incorrect regarding the overgrowth of algae?
a. The algae are heterotrophs.
b. The nitrogen in the fertilizer is in the ammonium form, the preferred nitrogen source of most microbes.
c. The phosphorus in the fertilizer is in the phosphate form, the preferred phosphorus source of most microbes.
d. The carbon source for these algae is not limiting in lakes.
e. Lakes have sufficient micronutrients for algae to grow

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