1. what are some similarities between the dogs pictured? what are some differences? . 2. what are some ways you can divide these dogs into groups? 3. how could you improve your dichotomous key? 4. why is it important to classify things?

Describe the particles of all three phases of matter in the root beer float. (how are the particles arranged and moving? )

Identify and describe the three ways that mutations affect organisms.

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.