What is a blastula? a solid ball of cells. a long sheet of cells. a hollow ball of cells. a hollow tube of cells.

an animal embryo at the early stage of development when it is a hollow ball of cells.

Population is a group of the same species living in the same area. The population can be affected by its surroundings. Birth, death, carry capacity, fires, or prey-predator interactions. The moose and wolves predator-prey relationship shows the fluctuation due to the affects. Moose population increase when they are provide with food and can reproduce. Wolves population have increased when they are able to catch the moose and keep the moose from other species that are fast and get some of the moose. The moose population decrease when wolves catch their calves or older wolves and the rate of reproduction is low. The wolves population is decreased when the weather is not great, the wolves will stay in their pack and not leave to reproduce.