The presence of vertebral column or notochord at any stage of life in any organism is the characteristic of vertebrate.
Explanation:
An animal is vertebrate if it fulfils the following criteria:
Presence of vertebral column or notochord.
Presence of endoskeleton or backbone.
The spinal cord runs above the vertebral column.
Humans embryo has notochord which becomes a vertebral column.
The alimentary canals end in the anus.
Mouth is present ta the anterior side of the vertebrate.
Have legs, fins or wings for movement.
Presence of a nervous system and sensory organs.
Presence of skin, lungs or gills.
Presence of a circulatory system.
Vertebrates include fish, amphibians, reptiles, birds and mammals.
Answer:
<em>Option 4, an autoimmune disorder, is the correct answer.</em>
Explanation:
An autoimmune disorder can be described as a disorder in which the immune cells of a body attack the own cells of a body.
Lupus can be described as an autoimmune disease which is long termed. In this disorder, a person's immune system attacks its own healthy cells. The immune system is unable to differentiate between the pathogenic cells and the healthy cells of the body. As a result, tissue damage is caused.
Answer:
Means to increase drag and prevent sinking is the correct answer.
Explanation:
Plankton avoid sinking by increasing their surface area and decreasing their density. Spines slow down sinking by adding surface area without increasing density. Defense against predation would be to sing below. Not the opposite.
The rigth answer is D.
The wavefront or wavefront is an equal phase surface of a wave, i.e., these points have the same travel time from the source. The concept is used to describe the propagation of waves such as sound or electromagnetic radiation (light, radio waves, etc.). In a homogeneous and isotropic medium, in which the waves propagate without deformation, two types of particular waves are distinguished according to whether the wavefronts are spheres (spherical wave) or planes (plane wave).
