The development and use of transgenic farm animals has not progressed as fast as the development of transgenic plant species. This may be due to all of reasons given EXCEPT .

Blood, made up of red and white blood cells, work together to form

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.

What is any method of measuring the age of an object or event in years, such as using atomic half-life?