That question, this incomplete. The full question is:
3. Three redwood trees are kept at different humidity levels inside a greenhouse for 12 weeks. One tree is left outside in normal conditions. The heights of the trees are measured once a week. What are the dependent variables, independent and the controlled variable of this experiment?
Answer:
- Independent variable: different humidity levels
- Dependent variable: the heights of the trees
- controlled variable: the types of trees
Explanation:
An independent variable is one that exerts an influence within the experiment and can be measured, acting on other elements to promote the observation of a result. As the experiment seeks to observe the influence of humidity on the height of the tree, we can say that humidity is the independent variable.
Dependent variable is that which is influenced by the independent variable to generate a result that can be observed, can also be measured. As the experiment wishes to analyze how the height of the trees was affected by the level of humidity, we can say that the height of the trees is the dependent variable.
Controlled variable is that which is present in the experiment in a constant and equal way, cannot be measured. This variable is the type of trees.
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.
A !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Answer:
I like dogs but cats hate dogs
