Q2.8. What proportion of the population must be vaccinated in order to achieve herd immunity for a strain of the flu with Ro= 3.0

What are the formed elements (cell or parts of cell) in blood and what are their functions ?

All organisms contribute some water to the water cycle by conducting

What are the two causes of density in deep current waters? a. salinity (how much salt) of the water and high temperaturesb. salinity (how much salt) of the water and low temperatures c. oxygen content of the water and high temperatures. d. oxygen content of the water and low temperatures