Natural substances are substances which occur in nature.
Some categories were excluded from such assessments, including hormones, like estrogen, which are natural substances.
A number of companies are replacing microbeads with natural substances such as ground-up fruit pits.
Many plastics were invented to imitate natural substances, like rubber, wood, bone, silk, hemp, or ivory.
Seaweed, in fact, is one of the most useful natural substances on the planet.
Bayer and McIntyre's invention, in postmodern fashion, creates natural substances that imitate plastics.
"The challenge is that athletes are turning to substances that mimic natural substances in your body".
Chemistry also is concerned with the utilization of natural substances and the creation of artificial ones.
Purine is not common, but the purine structure occurs in many natural substances.
One of the most familiar natural substances, rubber, is a polyisoprene.
Moreover, some scientists point out, there are many natural substances in food that breed tumors in rats or mice.
