When scientists look at very distant galaxies through powerful telescopes, they see the galaxies as they were millions or billions of year ago. why is this?

Which of the following are not matched correctly? cd8+: directly destroy infected or cancerous cells t reg cell: reduce the adaptive response once threat passes t l: activate cellular branch (cytotoxic t cells, macrophages, nk cells) t 2: stimulate b cells to make antibodies t (cd4+): mhc i