Answer:
The correct answer is e. <em>Postzygotic barrier.</em>
Explanation:
Different species can not mate and produce viable, healthy and fertile descendence, due to certain mechanisms of <u>reproductive isolation</u>.
These mechanisms involve different kinds of barriers that make it difficult for two different species to produce viable and fertile progeny.
One of these is the <u>postzygotic barrier</u>, which avoids the hybrid zygote to develope to adultness. In these situations, there is a mix of chromosomes that can not happen to meet or that they lack information.
There are cases in which the embryo dies, but some times the individual can reach some more advanced develope stages. If this is the case, in general, they can not survive because the organism is unhealthy. And if they reach adultness in good sate they can not leave descendence, as they are sterile.
Answer:
The correct answers are A, B and D. The Clean Air Act was important because it emphasized cost-effective methods to protect the air; encouraged people to study the effects of dirty air on human health; and created a regulation that makes any activities that pollute the air illegal.
Explanation:
The Clean Air Act is a federal federal law designed to control air pollution nationwide. The Environmental Protection Agency (EPA) is required to develop and enforce the regulations to protect the general public from exposure to air pollutants that are known to be dangerous to human health. The 1963 law established a basic research program, which was expanded in 1967. The main changes to the law, which require regulatory controls of air pollution, were promulgated in 1970, 1977 and 1990.
The 1970 amendments significantly expanded the federal mandate by demanding broad federal and state regulations, both for fixed sources of pollution (industrial) and mobile sources.
In 1990 provisions were added to deal with acid rain, depletion of the ozone layer and toxic air pollution, and a program of national permits of fixed sources was established. Also new requirements were established for the reformulation of gasoline, the adjustment of Reid vapor pressure (RVP), which measures the volatility of gasoline; and the norms to control the evaporation emissions of the gasoline.
The Clean Air Act is important because it was the first important environmental law in the United States to include a disposition regarding citizen demands. Numerous local and state governments have promulgated similar laws, either the execution of federal programs or to fill important loopholes at the local level in federal programs.
The main idea is that microorganisms are small and they live everywhere possible.
Sound waves are both compressional and longitudinal, (although we frequently draw them as transverse waves).
Longitudinal waves are where the particles of matter collide into one another, pushing them into the next and then oscillating back. This is how sound travels. This is also why sound can only travel through a medium, it cannot travel through a vacuum, as is shown here:
