Choose the answer that is the best topic sentence for the following paragraph.
There is a great difference between happy and unhappy
people. Happy people enjoy life. They are fun to be around,
and they think about other people. Happy people smile
often, while unhappy people rarely smile. Unhappy people
do not enjoy life, and they have trouble thinking about
anyone other than themselves. Unhappy people are no fun
to be around
O A. There is a great difference between happy and unhappy people.
OB. It should always be your goal to be a happy person.
Ο Ο Ο Ο
C. Happy people are the life of the party,
O D. Unhappy people cause trouble in many ways.

Which piece of evidence would best support reason #1? othe history of using animals for research extends asfar back as 322 bce, when early greek physician-scientists, such as aristotle and erasistratus,performed various experiments on living animals.animal research played an essential role in thedevelopment of herceptin and tamoxifen, twomedications that have already saved the lives ofthousands of women who have been diagnosed withbreast cancer.even those who believe in testing on animals when it is hnecessary for vital medical research practice what isknown as "the 3 rs-reduction, refinement, andreplacement to reduce the number of animals usedfor testing.biologists believe that chimpanzees share at least 98.4percent of the same dna as humans and gorillas shareat least 97 percent, making primates a popular andlikely choice for the testing of products intended for humans

By comparing part 1 and 2 of polar opposites what does it mean by polar opposites

Introduction to making a difference: it’s our world, too!