What effects do keystone specie shave on an ecosystem?

A. They make prey species extinct

B. They reproduce biodiversity

C. They keep populations of species balanced

D. They cause primary disturbances.

Which statement illustrates how human activities can most directly change the dynamic equilibrium of an ecosystem? Water pollution causes a decrease in fish populations in a river. A hurricane causes a stream to overflow its banks.

An example of a human disorder that is caused by a dietary deficiency rather thand heredity is? 1. Phenylketonuria 2. Sickle-cell anemia 3. Gaiter 4. Tay-sachs disease

What caused the mass extinction 65 million years ago that caused 75% of all species of plants and animals disappeared within a few million years?

Jason is studying a multicellular organism that can easily move around its environment. This organism must consume other organisms in order to receive energy. Which kingdom does the organism that Jason is studying most likely belong to?

Crossing over is a very important event in prophase 1 of meiosis! What happens during crossing over and what is the significance?

In order to grow, all organisms must

The DNA in a cell's nucleus encodes proteins that are eventually targeted to every membrane and compartment in the cell, as well as proteins that are targeted for secretion from the cell.

What similarity do animals and plants share?

This is a model of a bacterial cell. What statement about the structure and function of bacterial cell parts is correct? A) DNA is contained in a primitive nucleus. B) Energy for movement is generated in the pilli.

How can the locations where ancient fossils are found be used as evidence for continental drift