In comparing and contrasting different cultures, the gender roles:
a. are always about the same (male and female) in all cultures
b. are the same for males everywhere, but vary for females
c. are the same for females everywhere, but vary for males
d. vary and change for both males and females from culture to culture

d. vary and change for both males and females from culture to culture

Explanation:

Gender roles vary for both females and males across cultures. This can be observed in the way some societies are patriarchal and some are matriarchal. For example: in many Asian cultures, traditionally males head the families. It's their responsibility to engage in outside work and take important decisions for the family while women take care of household chores. This is reversed in some cultures like that present in Meghalaya, India. Here women are dominant figures in households. They inherit property, give their family name to children and after marriage the man comes to live with the woman's family. Hence gender roles are variable culture to culture.  

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explanation:

it provides an alternative energy pathway for the reaction to proceed.

a catalyst is a substance that speeds up the rate of a chemical reaction but is not consumed during the course of the reaction.

catalysts increase the rate of reaction without being used up. they do this by lowering the activation energy needed. with a catalyst, more collisions result in a reaction, so the rate of reaction increases. different reactions need different catalysts.

a catalyst works by providing an alternative reaction pathway to the reaction product. the rate of the reaction is increased as this alternative route has a lower activation energy than the reaction route not mediated by the catalyst.