<span>Vitamin D.
Vitamin D is made from 7-dehydrocholesterol and needs UV light in order to be activated. Because the children are not exposed to sunlight, they are receiving insufficient UV light.</span>
Answer:
B
Explanation:
Proteins are made up of smaller building blocks called amino acid.
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.
Three types of axonometric projection<span> are </span>isometric projection, trimetric projection. and dimetric projection.
Pectinate muscles are parallel ridges in the walls of the atria of the heart. The name is due to their resemblance to the teeth of a comb (pecten). The heart is the organ pumps blood to all parts of the body. It is made up of four chambers, that is, right and left ventricles, left and right atria, and the blood vessels, Pulmonary artery, pulmonary vein, aorta, and venacava. An auricles are pouch like structure that increase the total filling capacity of the atrium and also increase the volume of blood that an atrium is able to contain.
