het.step

network http://upload.wikimedia.org/wikipedia/commons/6/68/Social-network.svg

farmers https://c2.staticflickr.com/4/3506/3771823597_417cda8369_z.jpg

peanut http://upload.wikimedia.org/wikipedia/commons/4/4a/Peanut_9417.jpg

crowd http://global.fncstatic.com/static/managed/img/fn-latino/Crowd%20New%20York%20City.jpg

senate http://upload.wikimedia.org/wikipedia/commons/a/a6/US_Senate_Session_Chamber.jpg

schisto http://upload.wikimedia.org/wikipedia/commons/f/fb/Schistosomiasis_Life_Cycle.png

smallpox http://upload.wikimedia.org/wikipedia/commons/8/80/Poster_for_vaccination_against_smallpox.jpg

headlines http://upload.wikimedia.org/wikipedia/commons/e/eb/Salk_headlines.jpg

tbsmall https://upload.wikimedia.org/wikipedia/commons/f/f5/Mycobacterium_tuberculosis_8438_lores.jpg

influenza http://upload.wikimedia.org/wikipedia/commons/0/02/Flu_und_legende_color_c.jpg

book http://upload.wikimedia.org/wikipedia/commons/c/c5/Journal_of_Emerging_Infectious_Diseases_Jan_2013.jpg

maasai https://upload.wikimedia.org/wikipedia/commons/thumb/9/99/Maasai_tribe.jpg/800px-Maasai_tribe.jpg

inuit https://upload.wikimedia.org/wikipedia/commons/thumb/9/97/Inuit_Amautiq_1995-06-15.jpg/637px-Inuit_Amautiq_1995-06-15.jpg

dump_workers http://upload.wikimedia.org/wikipedia/commons/9/97/Payatas-Dumpsite_Manila_Philippines02.jpg

Lesotho_children https://upload.wikimedia.org/wikipedia/commons/4/4d/Lesotho_class.jpg

bento http://farm1.staticflickr.com/29/44276146_6021828b92_o.jpg