The lungs are

a. connected by the mediastinum

b. separated by the mediastinum

c. divided into seven lobes

d. divided into nine

The primary function of the respiratory system is to supply the blood with oxygen in order for the blood to deliver oxygen to all parts of the body. the respiratory system does this through breathing. when we breathe, we inhale oxygen and exhale carbon dioxide. this exchange of gases is the respiratory system's means of getting oxygen to the blood.respiration is achieved through the mouth, nose, trachea, lungs, and diaphragm. oxygen enters the respiratory system through the mouth and the nose. the oxygen then passes through the larynx (where speech sounds are produced) and the trachea which is a tube that enters the chest cavity. in the chest cavity, the trachea splits into two smaller tubes called the bronchi. each bronchus then divides again forming the bronchial tubes. the bronchial tubes lead directly into the lungs where they divide into many smaller tubes which connect to tiny sacs called alveoli. the average adult's lungs contain about 600 million of these spongy, air-filled sacs that are surrounded by capillaries. the inhaled oxygen passes into the alveoli and then diffuses through the capillaries into the arterial blood. meanwhile, the waste-rich blood from the veins releases its carbon dioxide into the alveoli. the carbon dioxide follows the same path out of the lungs when you exhale.the diaphragm's job is to pump the carbon dioxide out of the lungs and pull the oxygen into the lungs. the diaphragm is a sheet of muscles that lies across the bottom of the chest cavity. as the diaphragm contracts and relaxes, breathing takes place. when the diaphragm contracts, oxygen is pulled into the lungs. when the diaphragm relaxes, carbon dioxide is pumped out of the lungs. write one paragraph (at least 6 sentences) describing the path of oxygen through the respiratory system. also include why this "order of operations" is the way it is!

Warming up prepares the body for exercise in what way? a. muscularly b. cardiovascularly c. neurologically d. all of the above

The herpes viruses are important enveloped dna viruses that cause disease in vertebrates and in some invertebrates such as oysters. some of the human forms are herpes simplex virus (hsv) types i and ii, causing facial and genital lesions, and the varicella zoster virus (vsv), causing chicken pox and shingles. each of these three actively infects nervous tissue. primary infections are fairly mild, but the virus is not then cleared from the host; rather, viral genomes are maintained in cells in a latent phase. the virus can later reactivate, replicate again, and infect others.in electron micrographs of hsv infection, it can be seen that the intact virus initially reacts with cell surface proteoglycans, then with specific receptors. this is later followed by viral capsids docking with nuclear pores. afterward, the capsids go from being full to being "empty." which of the following best fits these observations? a) viral capsids are needed for the cell to become infected; only the capsids enter the nucleus.b) the viral envelope is not required for infectivity, since the envelope does not enter the nucleus.c) only the genetic material of the virus is involved in the cell's infectivity, and is injected like the genome of a phage.d) the viral envelope mediates entry into the cell, the capsid mediates entry into the nuclear membrane, and the genome is all that enters the nucleus.