Question

Types of keys are
(a)1
(b)2
(c)3
(d)4

Answer 1

Hint A printed or computer-aided device that is used to identify certain biological entities which include plants, animals, microorganisms, fossils, and pollen grains. They are used in various fields which include scientific and technical fields and are used to identify diseases, minerals, and soil types.

Complete answer:
There are three types of keys which are dichotomous, polyclave, and probability. Dichotomous keys are the most common keys that are a series of prepared statements which are known as couplets and describe the features of some organisms. A key is used by beginning with the first couplet and selecting the statement which fits the specimen. It directs the couplet to another couplet which provides the identity of the specimen. Dichotomous keys are of two types which are indented keys and bracketed keys. The indented keys allow the couplet with choices of the couplet at an equal distance from the left margin and follow the lead that was selected. The bracketed keys provide choices side by side of the couplet that is numbered or lettered. It is helpful if the previous couplet is provided alternate couplets are indented in some bracketed keys at the left margin. Polyclave keys are also known as multiple access or synoptic keys which allows the user to enter the key at any point and can choose the most obvious or important character of the specimen to identify it.

Additional information:
All potential variations of the species are not included in the dichotomous keys and they rely on the features which are not present in that season. It does not include all of the species of interest and misinterpret a feature or make a mistake. Writing a dichotomous key required some tips which include starting each coupled with a noun and avoiding unnecessary words. It avoids negatives and trichotomies and uses absent vs not present. The two statements of the couplet must be mutually exclusive and avoid vague terms. It does not include taxonomic names and uses certain features and avoids highly technical ones. Polyclave keys are easy to use and allow multi-entry that means the user can start from anywhere. It is easily computerized and is significant as the user can rely on the characters which are most easy to observe and to deal with.

So, the correct answer is '3'.

Note: Polyclave keys involve the process of elimination for identifying organisms. The state is followed by a number or a code in polyclave keys for the species possessing that feature and the user can select any character which is copied down in the list of species that possess that feature.