In the process of active transport, materials move from an area of lower concentration to an area of higher concentration. This requires more energy.
Diffusion involves the movement of molecules from an area of greater concentration to an area of lesser concentration.
In the process of osmosis, cells gain water by allowing it to flow from an area of higher concentration, outside the cell, to an area of lower concentration, inside the cell.
Cell membranes are selectively permeable, only allowing some molecules to pass through.
The nuclear membrane surrounds and protects the nucleus. Located inside the nucleus is the nucleolus, where RNA and ribosomes are created.
Vacuoles store food and other materials for later use by the cell. They also store waste, and in plant cells, they store water.
The aorta, the body's largest artery, carries blood directly out of the heart.
Depicts the heart beating.
Capillaries are the smallest blood vessels.
The carotid artery supplies the brain with oxygen.
The heart is divided into four chambers. The upper chambers are referred to as atria and the lower chambers are referred to as ventricles. The septum consists of a thick wall of tissue that separates the right and left sides of the heart.
The heart is responsible for circulating blood throughout your body.
Red blood cells play an important role in carrying oxygen and carbon dioxide throughout the body.
Air flows through the trachea, which branches into the bronchial tubes, which lead to the lungs. The lungs are made of millions of balloon-like structures called alveoli, which are surrounded by capillaries.
Valves in veins prevent blood from flowing backward.
There are eight main taxonomic levels in the modern taxonomic hierarchy.
Going from the broad to the specific, the house fly is in the domain Eukarya, the kingdom Animalia, the phylum Arthropoda, the class Insecta, the order Diptera, the family Muscidae, genus Musca, and species domestica.
Flatworms have bilateral symmetry. This means that if a line is drawn down the long axis of a worm's body, the two halves are nearly identical.
Embryology is the study of the development of embryos. By comparing embryological development of different organisms, scientists can identify relationships.
The classification system consists of a system of groups called taxa. Each taxon is a category into which related living things are placed. Taxa exist in a hierarchy, ranging from broad, general categories to narrow, specific categories.