An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination. In humans, it is called an embryo until about eight weeks after fertilization (i.e. ten weeks after the last menstrual period or LMP), and from then it is instead called a fetus.
The development of the embryo is called embryogenesis. In organisms that reproduce sexually, once a sperm fertilizes an egg cell, the result is a cell called the zygote, which possesses half the DNA of each of its two parents. In plants, animals, and some protists, the zygote will begin to divide by mitosis to produce a multicellular organism. The result of this process is an embryo.
Humans (variously Homo sapiens and Homo sapiens sapiens) are primates of the family Hominidae, and the only extant species of the genus Homo. Humans are distinguished from other animals by a relatively larger brain with a particularly well developed neocortex, prefrontal cortex and temporal lobes; enabling high levels of abstract reasoning, language, introspection, problem solving, culture through social learning, and other important mental capabilities which, combined with bipedal locomotion that frees the hands for manipulating objects, has allowed far greater use of tools than any other species. Humans are the only extant species known to build fires and cook their food, as well as the only known species to clothe themselves and create and use numerous other technologies and arts. The scientific study of humans is the discipline of anthropology.
Humans are uniquely adept at utilizing systems of symbolic communication such as language and art for self-expression, the exchange of ideas, and organization. Humans create complex social structures composed of many cooperating and competing groups, from families and kinship networks to states. Social interactions between humans have established an extremely wide variety of values, social norms, and rituals, which together form the basis of human society. Humans are noted for their desire to understand and influence their environment, seeking to explain and manipulate phenomena through science, philosophy, mythology, and religion.