Final answer:
Steep indifference curves with food on the vertical axis imply a consumer has a strong preference for food over housing, as they are willing to trade a lot of housing for a small amount of extra food.
Step-by-step explanation:
An indifference curve represents the combinations of goods that provide a consumer with the same level of satisfaction or utility. When these curves are plotted with food on the vertical axis and housing on the horizontal axis, the slope of the curves indicates the willingness of the consumer to trade one good for the other while maintaining the same level of utility. A set of indifference curves that are quite steep with respect to the horizontal axis implies that the consumer values food significantly more than housing. This is because a steep curve indicates that a large amount of housing would need to be given up to compensate for a small decrease in the amount of food, reflecting a high marginal rate of substitution. In other words, the consumer would be willing to give up a lot of housing to obtain a little more food, which shows a strong preference for food compared to housing.