QUES: Except for a few primitive organisms such as sponges (which have no nervous system) and cnidarians (which have a nervous system consisting of a diffuse nerve net), all living multicellular animals are bilaterians, meaning animals with a bilaterally symmetric body shape (that is, left and right sides that are approximate mirror images of each other). All bilaterians are thought to have descended from a common ancestor that appeared early in the Cambrian period, 485-540 million years ago, and it has been hypothesized that this common ancestor had the shape of a simple tubeworm with a segmented body. At a schematic level, that basic worm-shape continues to be reflected in the body and nervous system architecture of all modern bilaterians, including vertebrates. The fundamental bilateral body form is a tube with a hollow gut cavity running from the mouth to the anus, and a nerve cord with an enlargement (a ganglion) for each body segment, with an especially large ganglion at the front, called the brain. The brain is small and simple in some species, such as nematode worms; in other species, including vertebrates, it is the most complex organ in the body. Some types of worms, such as leeches, also have an enlarged ganglion at the back end of the nerve cord, known as a "tail brain".

Bilaterians are animals that have what?
What is the answer?
ANS: symmetric body shape
QUES: During mutualistic symbioses, the host cell lacks some of the nutrients, which are provided by the endosymbiont. As a result, the host favors endosymbiont's growth processes within itself by producing some specialized cells. These cells affect the genetic composition of the host in order to regulate the increasing population of the endosymbionts and ensuring that these genetic changes are passed onto the offspring via vertical transmission (heredity).

When the the host favors the endosymbiont's growth process what takes place?
What is the answer?
ANS: unanswerable
QUES: Egypt's economy depends mainly on agriculture, media, petroleum imports, natural gas, and tourism; there are also more than three million Egyptians working abroad, mainly in Saudi Arabia, the Persian Gulf and Europe. The completion of the Aswan High Dam in 1970 and the resultant Lake Nasser have altered the time-honored place of the Nile River in the agriculture and ecology of Egypt. A rapidly growing population, limited arable land, and dependence on the Nile all continue to overtax resources and stress the economy.

What year was Aswan High Dam completed?
What is the answer?
ANS:
1970