The main function of the human respiratory system is to question 4 options: a. produce carbon dioxide as a waste product. b. obtain oxygen out of the atmosphere. c. remove nitrogenous waste from the blood

a

explanation:

many plants naturally reproduce this way, but it can also be induced artificially. horticulturalists have developed asexual propagation techniques that use vegetative plant parts to replicate plants. success rates and difficulty of propagation vary greatly. monocotyledons typically lack a vascular cambium and therefore are harder to propagate.