It is found in animal tissues, but is never present in plants. (uen.org)
One type of valve, made from animal tissue and represented in the video by a pair of salsa dancers in pig and cow costumes, lacks durability. (aaas.org)
I believe a social trend toward smaller portions and eventual elimination of animal tissue in our diets would resolve the need for low - cost meat. (dotearth.blogs.nytimes.com)