A group of students hypothesizes that the amount of alcohol produced in fermentation depends on the amount of glucose supplied to the yeast. They want to use 5%, 10%, 15%, 20%, 25%, and 30% glucose solutions. 1)What is the independent variable? 2)What is the dependent variable? 3)What control treatment should be used? 4)What variables should be standardized (controlled)? 5)What type of graph is appropriate for presenting these data?

1) Glucose solutions

2) Amount of alcohol

3) Water

4) Yeast

5) Bar chart

Explanation:

1) Independent variable is the variable that is "intentionally altered" by the researcher only and is not affected by any other variable. The Independent variable in the question is the glucose solutions.

2) Dependent variable is the variable that is as a result of the independent variable. The dependent variable in the question is the amount of alcohol.

3) The control treatment that should be given to the control group should be water. The control group is the group in which other groups are usually compared to and are hence given the control treatment.

4) Control variable is the variable that is kept constant throughout the course of an experiment. The control variable in the question is the yeast.

5) The type of graph that will best represent these data is the bar chart. The glucose solution will be on the x-axis while the amount of alcohol produced will be on the y-axis.

answer: land bridge theory. land bridge theory held that shifting portions of dry land explained the finding of identical species on different continents. plate tectonic theory eventually eliminated the land bridge theory.

answer: decrease

a limiting factor is the one which decrease the abundance, distribution and causes extinction of the population of species in a ecosystem. here, predators including hawks, owls and snakes are the limiting factor for the population of mexican free tailed bat.   although bats are nocturnal animals as they forge for food at night these predators also may remain active during night which can decrease the population of the mexican free-tailed bats. also, these bats eat only one type of insects that are moths. the food can also be a limiting factor as all 400 members are dependent upon same type of food needs that are moths. the decrease in the moth population can cause decrease in population size of the mexican free-tailed bats.

therefore, the scenarios will most likely to decrease the population size of the mexican free-tailed bats.