An architect wants to use the riser-tread formula to design a stairway with a total rise of 9 feet, a riser height between 7 and 8 inches, and an odd number of steps. With the architect’s constraints, which of the following must be the tread depth, in inches, of the stairway? (1 foot = 12 inches)

Which scenario describes intraspecific, indirect competition? a. a peacock defends its territory against another peacock. b. lions and hyenas compete for the same prey animals. c. a male black bear eats fish in an area of a lake, so other black bears can’t. d. different species of birds fight over spilled popcorn on the ground.

The graph shows the populations of two species over time. which type of symbiotic relationship does the graph represent? a. commensal b. mutualistic c. parasitic d. parent-offspring e. predator-prey

What is the binomial name of the horsefly species that's golden backside inspired a 24-year old researcher to name it after a pop star in january 2012?