1. Which two structures have similar functions in plants and animals?
A. Plant stomata and insect spiracles
B. Tree bark and bison flat teeth
C. Flower pollen and animal lungs
D. Bison coat and insect exoskeleton

c. because step up transformer steps up the input voltage i.e increases the input voltage  

the number of turns are greater on the secondary side of step up transformer  

transformer does not handle dc current

i'm assuming that the correct answer is indeed the first one/ "a"..

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.