Mammal: does the mother's blood directly touch the embryo

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.

In general, are there any major differences that you can see? explain

Research question: why are the carrots that grew on the left side of the garden larger than the carrots that grew on the right side of the garden? which hypothesis is based on this research question? a comparison of people with gardens to people without gardens will show who is likely to live longer. b. carrots are thought to be good for your eyesight and should be eaten regularly. c. carrots that are provided lots of sunlight grow to a larger size than carrots grown in the shade. d. eating fresh vegetables every day is a healthy thing to do.