What are the four categories of taste

To date, there are five different types of taste receptors known: salt, sweet, sour, bitter, and umami.

The four categories of taste are generally salty, sweet, sour, and bitter.  However, there is some debate as to whether this is accurate.  

this protocol provides a detailed procedure for agarose-based ip to purify and enrich the protein of interest.

1. the geologists have established a set of principals that can can be used o determine the relative ages of rock. this principal is applied to sedimentary and volcanic rocks. the rocks exposed to wall of grand canyon has layers and by studying the number of horizontal layers in the rock(strata) the relative age can be determined. the layer first formed will appear at the bottom and the the layer of strata last formed appear at the top. by using this information the approximate age of rocks can be determined.

2. carbon dating is used to find the relative age of rock in numbers which means for the rocks that has age between 1-70,000 years.

3. for the rocks of age range between 1,000 - billion of years potassium-argon dating is used.