28. Good experiments have 2 key characteristics; they are
a. an experimental group and a confirmed hypothesis
b. analysis of the control group and an accurate prediction of the outcome
c. conducting the actual experiment and reporting the results
d. testing a single variable and using a control
No idea..
32. The 2 primary types of ocean currents are
a. wind and global currents
b. warm and cold water currents
c. ocean floor and gulf currents
d. surface and deep currents
D
38. 2 threats to ocean ecosystems are
a. nutrient runoff and industrial waste discharges
b. overfishing and entanglement of marine mammals in trawl nets
c. sewage and algal blooms
d. all of the above
Not sure..
39. What is the difference between an endangered species and a threatened species?
a. An endangered species has very low numbers while a threatened species' population is in decline
b. An endangered and a threatened species' population are both so low that they face extinction
c. An endangered species no longer exists and threatened species are on the verge of extinction
d. none of the above
D?
47. The composition of the atmosphere include gases, solid particles, and atmospheric dust. -True
Thanks
-MC
28. The correct answer is d. testing a single variable and using a control. To conduct a good experiment, you should focus on testing a single variable, which means manipulating only one factor while keeping all other factors constant. This allows you to determine the effect of that particular variable on the outcome of the experiment. Additionally, using a control group helps establish a baseline for comparison, as it is not exposed to the variable being tested. By comparing the results of the experimental group to the control group, you can determine if the variable had an effect.
32. The correct answer is d. surface and deep currents. Ocean currents can be classified into two primary types: surface currents and deep currents. Surface currents are driven by wind patterns and are found in the top few hundred meters of the ocean. They typically move in curved paths due to the coriolis effect. Deep currents, on the other hand, are driven by differences in temperature and salinity and are found deeper in the ocean. These currents transport heat, nutrients, and dissolved gases.
38. The correct answer is d. all of the above. There are several threats to ocean ecosystems, and all the options mentioned are valid threats. Nutrient runoff from agricultural activities and industrial waste discharges can lead to eutrophication, causing harmful algal blooms and disrupting the balance of marine ecosystems. Overfishing depletes fish populations and disrupts food webs, while entanglement of marine mammals in trawl nets can cause injury or death. Sewage discharge can introduce pollutants and pathogens into marine environments, leading to water contamination. Therefore, all the given options represent threats to ocean ecosystems.
39. The correct answer is d. none of the above. An endangered species and a threatened species are both classifications used to describe species at risk of extinction, but they have distinct criteria. An endangered species refers to a species that is facing a very high risk of extinction in the wild. Their population numbers are critically low, and they are at a high risk of disappearing entirely if not protected. On the other hand, a threatened species is a species that is likely to become endangered in the near future if current trends continue. Their population is declining, but they are not yet critically endangered. So, none of the given options accurately describes the difference between an endangered and a threatened species.
47. The statement is true. The composition of the atmosphere includes gases, solid particles, and atmospheric dust. Gases in the atmosphere, such as nitrogen, oxygen, carbon dioxide, and trace gases, play a crucial role in regulating climate and supporting life. Solid particles, such as dust, pollen, and salt particles, can be suspended in the atmosphere and influence air quality and visibility. Atmospheric dust refers to small solid particles, including soil particles, volcanic ash, and pollutants, that are present in the air.