Cardiorespiratory System. Consists of the heart, blood vessels, and the respiratory system The _____ circulates blood through the body, carrying oxygen, nutrients, and other key substances to the organs and tissues that need them It also carries away waste products so they can be used or expelled. î î î.
There are two main sources of vitamin A, animal sources and plant sources. Known as retinol, animal sources of this essential vitamin contain preformed vitamin A. Vegetable sources contain carotenoids, such as beta-carotene, which is converted to retinol by the body.itamin A that comes from animal sources is well absorbed and used more efficiently by the body then other sources of the vitamin. The two main sources of vitamin A from animal products are beef liver and turkey giblets. Other sources of this fat soluble vitamin include: 1  Chicken liver. 2  Cod liver oil.
The Roles of Vitamin A. Vitamin A is much more than just a vitamin that helps you see at night. It is a fat-soluble vitamin that plays a role in immunity, the body's development and maintenance of major organs. Available in two sources, vitamin A is derived from animals and from plants. Vitamin A from animal sources is preformed vitamin A and is active immediately. From plant sources, it is provitamin A â including a group of carotenoids, such as beta-carotene.