Why do polar bears have a thick layer of fat?

Would really appreciate it, i have an idea but not completely sure

Use the phylogenetic tree to the right to determine which statement below is true. organisms a and f are not related. organism e is more closely related to organism b than organism f. organisms c and d are more closely related than organisms a and b. phylogenetic trees

Astudent measured the amount of carbon dioxide (co2) produced by yeast during an experiment. use the data in the table at the right to answer the questions below. which variable is the dependent variable?