Stachybotrys chartarum (atra) is the black mold that has most been associated with media reports on the toxic effects of fungal exposure. It prefers gypsum wall board as a substrate and requires very high relative humidity levels to grow. Stachybotrys chartarum is known to produce the mycotoxin, satratoxin.
When total utility is rising with the increased consumption of a good, but is rising at a decreasing rate, marginal utility is negative. b. When total utility is rising with the increased consumption of a good, and is rising at an increasing rate, marginal utility is positive. c. At the maximum point of a hill-shaped total utility curve, marginal utility is infinite. d. When total utility is falling with the increased consumption of a good, but is falling at a decreasing rate, marginal utility is positive.
Assume the consumer utility function is defined by, where U is consumer utility, x and y are goods. Then the marginal rate of substitution can be computed via partial differentiation, as follows. Also, note that: where is the marginal utility with respect to good x and is the marginal utility with respect to good y.or example, if the MRS xy = 2, the consumer will give up 2 units of Y to obtain 1 additional unit of X. As one moves down a (standardly convex) indifference curve, the marginal rate of substitution decreases (as measured by the absolute value of the slope of the indifference curve, which decreases).