I knew I had reached my ___ for pain when I had to take the medicine for any relief.

- pallor
- expound
- understatement
- threshold

What is the best meaning for obscure in this line from the passage? a) ancient b) dark c) royal d) unknown

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

Context clues can be definitions, examples, synonyms, or antonyms. the word root can give you an idea of the word’s meaning. affixes can you determine the word’s form and meaning. use the drop-down menus to identify the root in each difficult word. automatic: gratify: untenable: