What does it mean for a cell membrane to be selectively permeable?
(a) it allows some substances to pass through but blocks the passage of others.
(b) it allows molecules to pass through if they are under a certain size.
(c) it allows only water molecules to pass through.
(d) it blocks the passage of most substances.

Assume that a student is given two different models of bacteria, with one model consisting of big bacteria and the other consisting of small bacteria. how can the student demonstate the theory of endosymbiosis using the models

What would most likely happen to a unicellular organism if it was exposed to a hypotonic solution for an extended period of time?

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