Top. A horizontal asymptote is a y-value which a function approaches. The asymptote is parallel to x axis, so is of the form y = a, for all real values of a. Thus if f(x) = y is a function, then y = a, becomes undefined for the function, then the line y = a, is called the asymptote for the function y = f(x).
The African armyworm (Spodoptera exempta) also called okalombo, kommandowurm, or nutgrass armyworm, is an African moth. It is a very deleterious pest, capable of destroying entire crops in a matter of weeks.
Earthworms prefer to eat at night, though, rather than in the day. That is why they are also called nightcrawlers. Besides adding nutrients to the soil, earthworms keep the soil healthy by tunneling. Worms do not have claws or paws to make tunnels, but they do have mouths. As they eat (and eat and eat), they create tunnels that keep the soil open and full of paths for water and air.