In biology, an organism is any contiguous living system, such as an animal, plant, fungus, archaeon, or bacterium. All known types of organisms are capable of some degree of response to stimuli, reproduction, growth and development and homeostasis. An organism consists of one or more cells; when it has one cell it is known as a unicellular organism; and when it has more than one it is known as a multicellular organism. Most unicellular organisms are of microscopic size and are thus classified as microorganisms. Humans are multicellular organisms composed of many trillions of cells grouped into specialized tissues and organs.
An organism may be either a prokaryote or a eukaryote. Prokaryotes are represented by two separate domains, the Bacteria and Archaea. Eukaryotic organisms are characterized by the presence of a membrane-bound cell nucleus and contain additional membrane-bound compartments called organelles (such as mitochondria in animals and plants and plastids in plants and algae, all generally considered to be derived from endosymbiotic bacteria).[1] Fungi, animals and plants are examples of kingdoms of organisms within the eukaryotes.
Estimates on the number of Earth's current species range from 10 million to 14 million,[2] of which only about 1.2 million have been documented.[3] More than 99% of all species, amounting to over five billion species,[4] that ever lived on Earth are estimated to be extinct.[5][6] In July 2016, scientists reported identifying a set of 355 genes from the Last Universal Common Ancestor (LUCA) of all organisms living on Earth
<span>The answer is extracapsular cataract extraction (ECCE). It is
a kind of eye surgery in which the lens of the eyes are removed, leaving the
elastic capsule covering the lens which is left partially attached to let the
implantation of an intraocular lens (IOL). This approach is compared with
intracapsular cataract extraction (ICCE), an older procedure in which the
surgeon detached the complete lens within its capsule and left the eye aphakic
(without a lens). The patient's vision was corrected after intracapsular
extraction by extremely thick eyeglasses or by contact lenses. There are two
major types of ECCE: manual expression, in which the lens is removed through a slit
made in the cornea or the sclera of the eye; and phacoemulsification, in which
the lens is shattered into fragments inside the capsule by ultrasound energy
and removed by aspiration.</span>
When it helps you achieve you goals and be proactive with assignments
Menstruation is triggered by a drop in the levels of progesterone. It is a hormone in the body that functions to regulate and stimulate a number of functions especially in females. It is a sex hormone and has an important role in pregnancy.
