The y chromosome is believed to have evolved from the x chromosome by a series of steps, including all of the following except: a. suppression of crossing over, keeping the maleness gene associated with other male trait genes. b. mutations at other genes affecting male traits. c. a mutation on a proto-x chromosome causing maleness d. degeneration of other genes due to lack of crossing over. e. actually, all of these are proposed steps in the evolution of the y chromosome.

Which of the following statements is correct in hour our immune system responds to a potential pathogen? a. the adapted immune system will call on the innate immune system to destroy the pathogen. b. b cells will start reading the antigen code immediately and call t cells to assist in destroying the pathogen. c. the skin will be the first line of defense, and then the many phagocytes in the bloodstream will attempt to consume the possible pathogen. d. the t-cells in the adapted immune systems are the first to recognize the pathogen vaccines are weakened forms of disease causing microorganisms, which are given to patients to prevent disease. after the vaccine is administered, the immune system responds by creating a(n) to recognize the a. antigen, antibody b. antibody, antigen c. antibody, antibiotic d. antibiotic, antibody

The image shows a group of fish. the type of social behavior shown in the image is called

Prior knowledge can be gained from personal experience and a) forming well-developed hypotheses. b) listening to opinions of other people on a topic. c) researching previous experiments and results on a topic. eliminate d) no other methods. it can only be gained by personal experience.