What is the primary function of the respiratory system?

question 5 options:

1)

transportation of blood

2)

oxygenate blood

3)

absorption of nutrients

4)

none of the above

Which best explains why viruses do not have special structures or enzymes that allow them to make their own food? viruses can use energy in living cells that they infect. viruses can replicate inside a host that they infect. viruses can cause contagious illnesses in host cells. viruses integrate their rna or dna into infected cells.

Common commercial benefits of microorganisms include synthesis ofa. insulin.b. antibiotics.c. aspirin.d. antibiotics and aspirin.e. antibiotics and insulin.

Classify the structures as homologous or analogous, depending on their structure and function.