The first evidence of modern human traits, including increasing brain size and dependence on material culture shows up in Homo habilis. Even though they are species<span> of genus </span>Homo, they are not similar to people nowadays at all. <span>In </span>palaeoanthropology, these species were the first ones who left Africa and started to move and spread along Eurasia, which is one the main facts and characteristics of Homo habilis.
The stability of atoms depends on whether or not their outer-most shell is filled with electrons. If the outer shell is filled, the atom is stable. Atoms with unfilled outer shells are unstable, and will usually form chemical bonds with other atoms to achieve stability.
<span>Organisms all possess DNA as their genetic material. What differentiates them (and their DNA) is the sequence of base-pairs within the DNA. The base-pairs are actually specific sequences of nucleotides (i.e. adenine , thymine, guanine and cytosine, labelled A, T, G, and C respectively) which encode genes. In other words, the DNA in each organism is made of these bases, but their sequences differ from organism to organism.</span>
Vascular plants<span> have two distinct organ systems: a </span>shoot<span>system and a </span>root<span> system. The </span>shoot<span> system consists of two portions: the vegetative (non-</span>reproductive<span>) parts of the plant, such as the leaves and the stems; and the </span>reproductive<span> parts of the plant, which include flowers and fruits.</span>
