concentric rings of bone matrix.
minute pores in the epidermis of a leaf or stem which allows for movement of gases and water...
blood vessels that transport deoxygenated blood from the heart to the lungs.
facing away from the stem (the lower surface of a leaf).
a heart chamber that receives blood from the body or lungs.
a timespan in the Earth's history. The sub-division of an era.
Books
Study Help
Find Definitions
Quick Revision
