It depends on which virus you are referring to specifically. Viruses come in many shapes and types; their variations are tremendous.
For HIV and Influenza, viruses acquire their envelops after maturation, during the budding off or detachment stage from the host cell.
Hope this helps! :)
In 1869 Mendeleev put together the periodic table
The highest level of organization for living things is the biosphere; it encompasses all other levels. The biological levels of organization of living things arranged from the simplest to most complex are: organelle, cells, tissues, organs, organ systems, organisms, populations, communities, ecosystem, and biosphere.
Answer:
Jaws and a swimming bladder
Explanation:
A defining characteristic between sharks and rays that distinguish them from ray-finned fish is the *possession of jaws in sharks* and rays;and the *possession of swimming bladder in ray-finned fishes*.
Characteristics of sharks and rays are as follows :
They are cartiiliginous fishes; they possess *strong jaws* lined with teeth; body dorsoventrally flattened, fusiform (spindle shaped) with heterocercal tail(diphycercal in Chimaeras); paired fins; *no swimming bladder or lungs*; pelvic fins in males often modified to form clappers; Gill arches internal to gills; reduced notchord; lateral-line system; paired nostrils; internal nares absent; separate sexes; internal fertilization and direct development; oviparous, oviparous, or ovoviviparous. Examples include, Spiny dog fish or dog shark, Ray Raja, Chimaera.
Characteristics of ray-finned fishses:
They generally lack paired fins; no internal nares; *air sacks usually function as swimming bladder*; skeleton usually well ossified. Blind olfactory sacs (do not open into the mouth); Tail homocercal. Examples include Tilapia, Claris,and Polypterus.
