Answer:
The structure of plant roots, stems, and leaves facilitates the transport of water, nutrients, and photosynthates throughout the plant.
Explanation:
The waste products of respiration are Co2 and H20.
Answer:
D
Explanation:
Parasites do not directly kill their host
Answer:
<em>a. Cross-sectional study</em>
Explanation:
A cross-sectional analysis <em>includes at one particular point in time looking at data from a population.</em> Participants are chosen based on specific variables of interest in this type of study.
For developmental psychology, cross-sectional experiments are often used, but this approach is also used in many other fields, including social science and education.
Answer: Mercury has been well known as an environmental pollutant for several decades. As early as the 1950's it was established that emissions of mercury to the environment could have serious effects on human health. These early studies demonstrated that fish and other wildlife from various ecosystems commonly attain mercury levels of toxicological concern when directly affected by mercury-containing emissions from human-related activities. Human health concerns arise when fish and wildlife from these ecosystems are consumed by humans.
During the past decade, a new trend has emerged with regard to mercury pollution. Investigations initiated in the late 1980's in the northern-tier states of the U.S., Canada, and Nordic countries found that fish, mainly from nutrient-poor lakes and often in very remote areas, commonly have high levels of mercury. More recent fish sampling surveys in other regions of the U.S. have shown widespread mercury contamination in streams, wet-lands, reservoirs, and lakes. To date, 33 states have issued fish consumption advisories because of mercury contamination.
These continental to global scale occurrences of mercury contamination cannot be linked to individual emissions of mercury, but instead are due to widespread air pollution. When scientists measure mercury levels in air and surface water, however, the observed levels are extraordinarily low.
Explanation:
