Which claim does the author make through a discussion of jenner’s discoveries related to cowpox and smallpox?

jenner’s research distinguished cowpox from smallpox.
jenner’s research led to the creation of a smallpox vaccine.
jenner’s research was responsible for the elimination of many diseases.
jenner’s research was a result of a conversation he had with a dairymaid.

anwer is b

By what percent will the product of two numbers change, if the first number increases by 70%, while the second number decreases by 40%.

Alaser tag arena sells two types of memberships. one package costs $325 for one year of membership with an unlimited number of visits. the second package has $125 enrollment fee, includes five free visits, and costs and additional $8 per visit after the first five. how many visits would a person need to use for each type of membership to cost the same amount over a one-year period?

Summarize the work of famous environmental scientists of the past.