Amicroscope reveals one hundread similar cells arranged end to end in a space of 1 millimeter the average length of each cell must be ?

What are some possible short and long term medical concerns for crew members on longer space exploration trips

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.

Apaleontologist finds a plant fossil that shows that the plant had seeds. what can the paleontologist conclude?