The infection of cells by the human immunodeficiency virus (HIV) requires the virus to bind to the cell surface molecule CD3 and a second coreceptor molecule, CCR5 or CXCR4. a. True
b. False

in the year 2850, humans successfully colonized mars. the martian modules that were constructed could hold only a small population of people. it is now a century later, and the population on mars has grown to 600 people. of the current mars population, 45 people express the recessive phenotype for phenylketon- uria (pku) syndrome (pp genotype).

explanation: