Sound waves require a medium to travel through, such as a solid, liquid or gas because
a) waves cannot move through a vacuum.
b) sound only works within certain pressures.
c) waves only work within certain temperatures.
d) sound is molecules bumping into one another.

Which of the following statements concerning the influence of culture on ethnic identity formation is accurate? a. one will reject ethnic identity if cultural stereotypes are encountered. b. if one’s ethnic city is different from the dominant cultural group, then one’s ethnic identity you will become weekend. c. if an the ethnic group is excepted by dominant culture, then ethnic identity formation can be a difficult process. d. similarity to the dominant culture can determine how easy it is for one to except ethnic differences.

Compare and contrast physical changes with chemical changes.

The scheme below is from a series of reactions that are part of a synthesis of vitamin a. answer the following questions with reference to this scheme. (i) what is "reagent a"? (ii) draw a step-by-step mechanism which explains the formation of compound c from compound b (iii) which reagents would you use to form compound e from compounds c and d (reagents b and c)? for each reagent suggested above in (ii) explain the role of the reagent in the reaction to (iv) form compound e. you may wish to do this by drawing a mechanism. 1. addition of reagent a но reagent a 2. н,о" thо oh нон-с compound a. compound b. compound c .ch-оh 1. reagent b "сно 2. reagent c сh oh compound e. compound d.