Final answer:
The necessity of exposure to air for microbial growth can be true or false depending on the type of bacteria. Bacteria have 70S ribosomes, not 80S, making the second statement false.
Step-by-step explanation:
The question addresses two statements about microbiology which is a part of Biology.
The first statement is 'Exposure to air is necessary for microbial growth.' This statement can be considered true or false depending on the type of microbe. Aerobic bacteria require oxygen to grow, making the statement true for them. However, anaerobic bacteria can grow without oxygen, making the statement false for such bacteria. Therefore, the statement is not universally applicable to all microbes.
The second statement, 'Bacteria have 80S ribosomes each composed of a 60S large subunit and a 40S small subunit,' is false. Bacteria typically have 70S ribosomes, which consist of a 50S large subunit and a 30S small subunit. The 80S ribosomes are characteristic of eukaryotic cells, not prokaryotic bacteria.