Oxygen-poor blood enters the heart through the right atrium. From there blood flows through the tricuspid valve into the right ventricle. When the heart contracts during the diastolic phase, this blood is pumped out through the pulmonary arteries that run toward the lungs. At the lungs, the blood is circulated through a series of progressively smaller arterioles until it flows through capillaries lining the lungs' alveolar sacs. It is here that gas exchange takes place as oxygen is taken up by the blood, and carbon dioxide is released into the waste air.After oxygenation, the fresh blood is circulated back through the bronchial veins and into the pulmonary veins. These run from the lungs and drain into the heart's left atrium. During the systolic phase of the heartbeat, the mitral valve under the left atrium opens and permits blood to pass into the left ventricle. This chamber is heavily muscled and it has the power to pump the oxygen-rich blood out through the aorta and into the rest of the body.
Answer:
is d. a destruction of ecological habitats
Explanation:
Answer:A
Explanation: more resources are usually need it for the initial set up and planning of traditional large scale agriculture techniques.
Answer:
D. is responsible for most of the skin's structural strength.
Explanation:
A. contains no blood vessels.
False. The dermis contains blood vessels together embedded in it along with the sweat and sebaceous or oil glands, hair follicles, and nerve endings.
B. functions as a padding and insulation.
False. The fat layer that is located below the dermis is the one responsible for padding and insulation.
C. is divided into three distinct layers
False. The dermis is divided into only two separate layers. These are the papillary layer or the upper layer and the reticular layer or the lower layer.
D. is responsible for most of the skin's structural strength.
Yes, the dermis functions for providing the skin's structural strength because of it's thick fibrous and elastic tissue layer. This layer consists primarily of collagen and elastin that also allows for the skin's flexibility.
E. is made of epithelial tissue.
False. The dermis is made up of fibrous and elastic tissue. It is the epidermis which is composed of the epithelial tissue.
