The equinox of the southern hemisphere takes place when the vertical rays of the Sun cross the equator on their way southward.

People keep spending additional units of a particular resource on a want until their marginal benefit is  decreasing withgreater thanless thannot affected by  their marginal cost.

Which are practical examples of how people in the developed world could make a big difference in how much water they use check all that apply a. use lightbulbs that use less electricity b. consider using a composting toilet that does not use water c. avoid using your telephone during peak hours d. do not read books

What is the problem with blowing up large asteroids?