Video shows what sporophyte means. A plant (or the diploid phase in its life cycle) which produces spores by meiosis in order to produce gametophytes.. Sporo...
Concentric contraction involves a shortening of the muscles under loading and is used to accelerate the body or move an object, as when you suddenly move in the opposite direction to hit the baseball.
(concentric action) the 'true' form of contraction of a muscle in which it shortens against a load (which may be only that of gravity on the relevant body part), and so does positive work. Hence concentric exercise: that in which the principal agonists act concentrically.