Answer:
Something that is persistent remains over time; this is a key characteristic of DDT, which also happens to be a pollutant/pesticide. DDT is able to persist in an environment (as a pollutant) in part due to a phenomenon known as biological magnification. In simpler terms. once DDT enters an ecosystem/trophic structure, it gets worse as you go up the trophic levels; in other words, this means that the worst effects/concentrations of the pesticide will be felt in the uppermost trophic levels (your consumers rather than producers).
The basis for this, however, lies in the fact that organisms of a trophic structure/ecosystem consume each other; they feed on each other to survive (e.g. consumers feeding on producers, higher-level consumers feeding on lower-level consumers, etc.). Thus, once DDT gets into an ecosystem, it can only persist and spread in that ecosystem. Hope this helps :)
Answer:
B. The fifth sentence elaborates on an assertion made in the preceding sentence.
Explanation:
Answer B
Correct. In the fourth sentence, the authors make a claim about the role of mathematics in the sciences, asserting that “the more [mathematics] can be applied usefully within a science, the more advanced the science.” The fifth sentence begins with the conjunction “For,” which is commonly used to introduce reasoning that explains or clarifies an earlier statement. And indeed, the fifth sentence does explain why the application of mathematics helps advance a science: because mathematics functions as both a precise language and a means of measurement.
Answer:
expenses
Explanation:
The equation for profit is revenue-expenses
not prices: remember these as price tags on the bread you get at supermarkets
not revenue: revenue is the total amount of money made
not supply: completely unrelated to price
Answer:
A. Keep it, because it uses descriptive language to convey the writer’s perspective on advances in robotics and set up the topic of the passage.
Explanation:
Answer A
Correct. The underlined text uses descriptive adjectives and adverbs to describe today’s robots and the way they interact with humans. This descriptive language helps to convey the writer’s perspective on advances in robotics and also sets up the topic of the passage, which is how humans and robots interact. Therefore, the writer should keep the underlined text.
I. Older Americans are more likely to vote than younger Americans
