if asteroids brought 1 cm of water to earth every 5000 years, and the average depth of earth's oceans is 3700 m how many years would it take to fill the ocean

The serengeti plains are part of the african savanna ecosystem and are home to a variety of different species of plants and animals. the serengeti plains experience a seven-month period of seasonal drought each year, during which the ecosystem receives only four inches of rain and the availability of some resources becomes very scarce. which type of limiting factors does the seasonal drought in the serengeti plains affect?