They breathe through their skin. Air dissolves on the mucus of their skin, so they MUST stay moist to breathe. If worms dry out, they suffocate. As fresh air is taken in through the skin, oxygen is drawn into the worm's circulatory system, and the worm's hearts pump the oxygenated blood to the head area.
A gene is a small section of DNA?<span> that contains the instructions for a </span>specific<span>molecule, usually a </span>protein?. The purpose of genes?<span> is to store information. Each gene contains the information required to build </span>specific proteins<span> needed in an organism. The human genome</span>?<span> contains 20,687 </span>protein<span>-coding genes.</span>
<span>The answer is a. carbohydrates. The amount of potential energy in the molecule depends on the number of C-H bonds in the molecule. Carbohydrates have more C-H bonds. Thus, they can serve as energy storage. Other macromolecules have less C-H bonds. Thus, when energy is needed immediately, complex carbohydrates break down to simple carbohydrates and the energy is released.</span>
The extinct ancient human Homo erectus is a species of firsts. It was the first of our relatives to have human-like body proportions, with shorter arms and longer legs relative to its torso.
<h3>What are Homo erectus?</h3>
Homo erectus, an extinct species of Pleistocene archaic human, first appeared about 2 million years ago. Several human species, including H. heidelbergensis and H. antecessor, seem to have diverged from H. erectus, with the former being largely accepted as the ancestor of Neanderthals, Denisovans, and modern humans. Among the first recognizable representatives of the genus Homo are its specimens. The first known ancestor of modern humans, H. erectus, had a continental range that stretched from the Iberian Peninsula to Java. H. floresiensis and possibly H. luzonensis may have its origins in Asian populations of Homo erectus. H. erectus soloensis, from Java, dates to a time period between 117,000 and 108,000 years ago.
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