1 Hydrogen is the most abundant element in the universe. 2  Hydrogen isn't common in a pure form on Earth, but is mostly found as part of water. 3  Hydrogen is the main fuel of stars and the only fuel for red dwarfs. 4  The whole universe is thought to have been formed by a Hydrogen nucleus.
Noun. 1. hindlimb-a posterior appendage such as a leg or the homologous structure in other animals. hind limb. hind leg-the back limb of a quadruped. limb-one of the jointed appendages of an animal used for locomotion or grasping: arm; leg; wing; flipper. 1  Facebook.
The hindbrain contains several structures that regulate autonomic functions, which are essential to survival and not under our conscious control. The brainstem, at the top of the spinal cord, controls breathing, the beating of the heart, and the diameter of blood vessels.he preponderance of the cerebral cortex (which, with its supporting structures, makes up approximately 80 percent of the brain's total volume) is actually a recent development in the course of evolution.