168
(http://champaign.org/justkids/homework_help/science_and_environment/science_fair.html)
(http://champaign.org/justkids/homework_help/science_and_environment/inventions_inventors.html)
(http://champaign.org/justkids/homework_help/science_and_environment/endanged_species.html)
(http://champaign.org/justkids/homework_help/science_and_environment/prairies.html)
(http://champaign.org/justkids/homework_help/science_and_environment/rainforest.html)