Crossing over is thought to be evolutionarily advantageous because it continually shuffles genetic alleles into novel combinations. until recently, it was thought that the genes on the y chromosome might degenerate because they lack homologous genes on the x chromosome with which to pair up prior to crossing over. however, when the y chromosome was sequenced, eight large regions were found to be internally homologous to each other, and quite a few of the 78 genes represent duplicates. (y chromosome researcher david page has called it a “hall of mirrors.”) explain what might be a benefit of these regions.

Read the sentence. “yesterday we arrived late for the outdoor concert in the city gardens.” which words in the sentence are adverbs? a. late; city b. yesterday; outdoor c. yesterday; late d. outdoor; city

Which is an advantage of having memory cells when a pathogen is encountered for a second time. a) the memory cells are what proliferate into clones of cells in response to the binding of an antigen. b) memory cells are vital to the primary immune response in that they immediately recognize pathogens even at the first encounter. c) memory cells are essentially effector cells that are short lived and attack antigens even without having a receptor specific to that antigen. d) it ensures that more lymphocytes with a receptor specific to a particular antigen will be present than in a host that had never encountered that pathogen.

Group control group #1 experimental group yes yes yes control group #2 no new drug orange juice bed rest no yes no yes ves which of the following is the best explanation of why a second control group was included in this experiment? o a. to provide the volunteers in the study with something to drink o b. to prove that the common cold cannot be cured c. to confuse anyone who is trying to steal their new drug and sell it as their own invention o d. to researchers conclude that results are related to the new drug and not to the orange juice submit e previous