1. Blood is made up of specialised red blood cells and several different types of white blood cells. Is blood an example of a cell, tissue, organ and organ system? Explain your answer.

Explain how sequences of amino acids in proteins can be used to reveal relationships among organisms.

What is the main function of the central vacuole in a plant cell? a. absorbs energy from the sun to produce food b. holds water and maintains turgor pressure c. breaks down molecules to release energy d. contains the cell's genetic material

Asquirrel population lives in an area. over many years, a river in that area grows wider and stronger, eventually forming a canyon. the squirrel populations on the two sides of the canyon can no longer mate with each other and ultimately form distinct species. this is an example of