It is well known that cancer is not a single disease. it follows then that cancer does not have a single cause. it seems more likely that the occurrence of cancer is triggered by the interactions of multiple risk factors. what are some identified risk factors for cancer?

How quickly a drug enters your bloodstream also depends on

Samuel is a 63-year-old single man who works full time in a food processing plant. he has a history of esophageal cancer, which was treated successfully with anti-cancer drugs and surgery four years ago. his weight had been stable at 135 pounds until 6 months ago. since then, he has experienced an involuntary weight loss of 10 pounds. he complains of a poor appetite and being overly weak, tired, and irritable. he also complains of cracks at the corners of his mouth and a chronic sore throat, which concerns him, given his cancer history. his usual diet is fairly consistent. he states that he rarely eats breakfast because he starts work at 6 a.m. he eats two deli meat sandwiches, "usually pastrami or salami," and a soda at 10 a.m., and may eat a candy bar in the afternoon when he gets off work. he often prepares and eats a frozen dinner or pizza at home in the evening and routinely drinks "about four or five beers" before going to bed. occasionally, he cooks roast and mashed potatoes for dinner and may have cereal with milk for a snack before bed. he rarely eats vegetables or fruit. 1. considering samuel's alcohol consumption, which b vitamin may he be deficient in? a. pantothenic acid b. niacin c. riboflavin d. biotin e. thiamin

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.