Which sentence is punctuated correctly?
a. in first-period biology class we learned that, the ecosystem, is a fragile and sensitive thing.
b. the freshmen, were excited to hear about extra-credit opportunities in their algebra class.
c. getting her license proved to be more difficult and tricky, than she thought it would be.
d. in order to serve students best, school districts need to ask for additional funding.

Read the text of the barack obama speech “remarks by the president at the 50th anniversary of the selma to montgomery marches.” which options best explain obama’s rhetorical purpose in the speech? (select all that apply.) `to celebrate an important milestone in the history of civil rights `to explain to his audience why they should welcome immigrants into america `to inspire and motivate his audience to exercise their right to vote `to inform and educate his audience about the history of social injustice in america