Which type of junctions must there be between cells to form a barrier?

Aresearcher has developed two stains for use with seed plants. one stains sporophyte tissue blue; the other stains gametophyte tissue red. if the researcher exposes pollen grains to both stains, and then rinses away the excess stain, what should occur? a) the pollen grains will be pure red. b) the pollen grains will be pure blue. c) the pollen grains will have red interiors and blue exteriors. d) the pollen grains will have blue interiors and red exteriors.

The influenza virus cause the flu, but not other diseases. why?

15 ! come and answer! a(n) is the general term for an infectious disease that has spread across a city, region, or country.