Astudent performed an experiment to see if water temperature affects the level of activity in aquatic snails. the student set up four tanks with five snails in each tank. all four of the setups were identical in every way, except for the temperature of the water. in order to make the conclusions more valid, the student could:
(1) alter the ph of the water
(2) change the size of the tank
(3) carry out the experiment for a shorter period of time
(4) use a larger number of snails

Mike was adopted, and his biological family history is unknown. although he is healthy, he would like some understanding of his genetic makeup, including potential health risks and genes that he could pass on to his children. mike has heard about commercial laboratories that can compare segments of your dna to those of people with common hereditary diseases in order to give you some idea of how susceptible you are to the diseases. the results of these types of tests are highly inconclusive. if mike's dna showed that he shares similarities in a segment of dna with people who have a given disease, his chances of developing that disease or passing it on to his children may be slightly elevated, but they are not 100 percent. these tests can cost more than $2,500 and are not covered by many insurance companies. do you think that mike should undergo the genetic tests? explain your answer. what are the potential pros and cons of having such tests done? describe how the availability of these genetic tests might affect the frequency of genetic diseases in individuals and populations.

Freckles are a dominant trait in humans. both of the girls have the genotype ff for freckles. if either one marries a man with no freckles, what are the chances that their children will have freckles?

In 2015, about ten percent of total u. s. energy consumption was from renewable energy sources. renewable energy plays an important role in reducing greenhouse gas emissions. when renewable energy sources are used, the demand for fossil fuels is reduced. sanjay and his family want to cut back on their use of non-renewable resources at home. they are thinking of an alternate way to heat their home without adding more greenhouse gases or pollutants to the environment. which renewable resource would not fit into their plan? a) solar power b) burning wood c) constructing a wind turbine eliminate d) generating hydroelectric power