The sun does however, revolve about a point in the centre of our galaxy. Taking entire solar system with it at a speed of 220 km/s. This period of orbit takes 225 million years. The sun revolves at about once every 25days at its equator and up to 30 days near its poles.
2) Chemical substances in food dissolve in saliva
Substances form the food need to be dissolved and and a little bit degraded (by teeth and some of the enzymes in the mouth) in order to react chemically with taste receptors
1) Taste receptors are stimulated
Taste receptors are located in the oral cavity, usually on the tongue but also pharynx and the epiglottis (receptors are placed on taste buds within papilla on tongue)
3) Signals are sent to the thalamus by the facial nerve
From the ventral posterior medial nucleus in thalamus sensation is projected to the gustatory cortex
4)The gustatory cortex processes taste perception
The sensation of taste includes: sweetness, sourness, saltiness, bitterness, and umami
The modern taxonomists classified organisms on the general basis of evolutionary, morphological, and genetic traits
Explanation:
- Evolutionary relationships provides the phylogeny of evolutionary ancestors and descendants
- Homologous structures are structures which look the same but perform different functions
, like bones of a human leg compared to bones on a bird's wing
- Analogous structures have different structure but same function like an insect’s and a bird’s wing
- Embryo developmental pattern and similar relationships
- Similarities in DNA and protein sequencing in related organisms
The above basis provided modern taxonomists to classify organisms according to the various disciplines like Genetics, Cytology, Embryology, Physiology, Anatomy and many more.
The solar system formed about 4.6 billion years ago.