Asteam shovel lifted 1,100 pounds of dirt 1 foot in 1 second. how many horsepower is this?

15 ! come and answer! a(n) is the general term for an infectious disease that has spread across a city, region, or country.

Grasses--> mice--> cats--> coyotes suppose 10,000 units of energy are available at the level of the grasses. what is the total number of energy units lost by the time energy reaches the coyote?

Which of the following statements is true about the relationship between genetic variation and natural selection? a. genetic variation must be present in a population before natural selection can act on it. b. genetic variation arises in a population as a result of natural selection. c. natural selection can act on a population whether there is genetic variation within the population or not. d. after natural selection acts on a population, the amount of genetic variation in the population always increases.