human trafficking (the buying and selling of persons as a goods); slave trade

throughout the world

seriousness

serious, deep, heavy (topic), profound (change), weighty (matter)

to buy and sell

trade - selling and buying

the human body / personal

the human body

question, problem on homework etc. / a question; a matter (of time etc.) / a problem (something that needs to be dealt with); a trouble / an issue; a matter

becoming more serious