If a researcher introduced a suspected pathogen into many healthy hosts, but none of them became sick, what could this indicate?

24-karat gold is considered to be pure gold. 18-karat gold is considered to be about 75% gold. what is 18-karat gold considered a mixture rather than a pure substance? a) it has a variable composition of other elements and minerals. b) its color is different than pure gold. c) the gold atoms are not arranged in a repeating pattern. d) it can be melted and transformed into a different substance.

1. how did conditions in germany and europe at the end of world war i contribute to the rise and triumph of nazism in germany? 2. how did the german government under nazi rule build support among the german people? 3. how did nazi germany gradually isolate, segregate, impoverish, and incarcerate jews and persecute other perceived enemies of the state between 1933 and 1939? 4. how did the nazis lead germany to war in europe and, with their collaborators, kill millions—including systematically murdering six million jewish people? 5. why is learning about the holocaust important? so we don’t repeat history.

Dr. robbins wants to know if there are different opinions regarding the value of public school education between native americans who have at least one relative who attended indian boarding school and native americans who have no family experience with indian boarding school. dr. robbins contacts 35 native american participants in each group. he wants each group to include younger as well as older adults, and a mix of male and female participants. he asks each person to complete a survey about their attitudes toward public education. the design of this study is: