Which of these experimental designs could lead to bias?
a) two mice are given the choice between swiss and american cheese.
b) phil and bart race down the street to determine who is the fastest.
c) a car company pays participants to test drive and evaluate their new auto.
eliminate
d) a private company uses a random taste test of three different, unidentified soft drinks.

What overall charge must all compounds have

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.

The mass of a neutron is equal to the mass of a proton plus the mass of an electron. true or false false true