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antiseptic1488 [7]
3 years ago
9

A controlled experiment___. A. Includes one group for which the scientist controls all variables. B. Includes at least two group

s, one of which does not receive the experimental treatment. C. Includes at least two groups, one differing from the other by two or more variables. D. Is repeated many times to ensure that the results are accurate.
Biology
1 answer:
notsponge [240]3 years ago
5 0

Answer:

The correct answer is:

Includes at least two groups, one of which does not receive the experimental treatment. (B)

Explanation:

A controlled experiment is made up of at least two groups of participants (subjects). One group (the test group) receives the experimental treatment, which can be an intervention or a new drug to be tested etc, and the effect of the treatment on the subjects is measured, while the second group of similar subjects also known as the control group acts as a baseline and do not receive the treatment or intervention. They act as a baseline to ensure that the change observed in the treatment group was brought about as a result of the treatment.

<em>Note that repeating the experiment several times does not ensure accuracy of the result, rather it ensures reliability of the results hence option D is not correct</em>

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The calcium and phosphorus balance should be kept at what ratio for swine?
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Answer:

We determined that if phosphorus is provided at the required level of 0.33%, the optimal ratio of calcium to phosphorus is 1.39:1 or 1.25:1 to maximise daily gain and gain-to-feed, respectively. To optimise bone ash, which is important for breeding sows, the ratio is 1.66:1,”

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Which climate conditions are typical of regions near the North Pole and the South Pole?
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Cold and extremely down climate is experienced in these locations, this is due to the lack of exposure to the sun's rays. The North and South Pole of the earth are also responsible for many meteorological and astronomical occurrences that protects earth and its inhabitants from the harsh exposure to the sun's rays.

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What compound is found at the reaction center of a photosystem?
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D. Chlorophyll a

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6 0
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2 years ago
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I need help with modeling a carbon cycle, do you mind helping me? :)
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Explanation:

The Carbon Cycle

The element carbon is a part of seawater, the atmosphere, rocks such as limestone and coal, soils, as well as all living things. On our dynamic planet, carbon is able to move from one of these realms to another as a part of the carbon cycle.

Carbon moves from the atmosphere to plants. In the atmosphere, carbon is attached to oxygen in a gas called carbon dioxide (CO2). Through the process of photosynthesis, carbon dioxide is pulled from the air to produce food made from carbon for plant growth.

Carbon moves from plants to animals. Through food chains, the carbon that is in plants moves to the animals that eat them. Animals that eat other animals get the carbon from their food too.

Carbon moves from plants and animals to soils. When plants and animals die, their bodies, wood and leaves decays bringing the carbon into the ground. Some is buried and will become fossil fuels in millions and millions of years.

Carbon moves from living things to the atmosphere. Each time you exhale, you are releasing carbon dioxide gas (CO2) into the atmosphere. Animals and plants need to get rid of carbon dioxide gas through a process called respiration.

Carbon moves from fossil fuels to the atmosphere when fuels are burned. When humans burn fossil fuels to power factories, power plants, cars and trucks, most of the carbon quickly enters the atmosphere as carbon dioxide gas. Each year, five and a half billion tons of carbon is released by burning fossil fuels. Of this massive amount, 3.3 billion tons stays in the atmosphere. Most of the remainder becomes dissolved in seawater.

Carbon moves from the atmosphere to the oceans. The oceans, and other bodies of water, absorb some carbon from the atmosphere. The carbon is dissolved into the water.

Carbon dioxide is a greenhouse gas and traps heat in the atmosphere. Without it and other greenhouse gases, Earth would be a frozen world. But since the start of the Industrial Revolution about 150 years ago humans have burned so much fuel and released so much carbon dioxide into the air that global climate has risen over one degree Fahrenheit. The atmosphere has not held this much carbon for at least 420,000 years according to data from ice cores. The recent increase in amounts of greenhouse gases such as carbon dioxide is having a significant impact on the warming of our planet.

Carbon moves through our planet over longer time scales as well. For example, over millions of years weathering of rocks on land can add carbon to surface water which eventually runs off to the ocean. Over long time scales, carbon is removed from seawater when the shells and bones of marine animals and plankton collect on the sea floor. These shells and bones are made of limestone, which contains carbon. When they are deposited on the sea floor, carbon is stored from the rest of the carbon cycle for some amount of time. The amount of limestone deposited in the ocean depends somewhat on the amount of warm, tropical, shallow oceans on the planet because this is where prolific limestone-producing organisms such as corals live. The carbon can be released back to the atmosphere if the limestone melts or is metamorphosed in a subduction zone.

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