Electron microscope can only view specimens that are no longer living true or false?

In cattle a single gene with two alleles determines fur color the fur can be red white or roan roan fur has both red and white hair which of the following statements is true a the allele for roan fur color is dominant over red and white fur color b the allele for red fur color is dominant over white and roan fur color c the roan and white alleles are expressed independently of the other d the red and white alleles are expressed independently of each other

In two sentences explain the differences of neutrophil and macrophage

What characteristic makes a cell membrane selectively permeable