who give the trinomial system of classification in animals and binomial in plants?

Answer 1

carolus linneaus

Answer 2

The classification of animals and plants is not
strictly binomial in either plants or animals. The
binomial system was not invented by Linnaeus, but
it was for the first time applied uniformly to all
plants and animals by him. His works are used as
the official starting point of nomenclature for both
plants and animals, as pointed out in another
answer. What this means is simply that any names
given to an organism earlier can be ignored.

The addition of a third (or even, sometimes, a
fourth, fifth or sixth) name came about for several
reasons. These reasons are likely to be different
for plants and animals, which have different rules
of nomenclature that govern their names.

Sometimes an animal shows differences in some
ways (color or length of appendages are two such)
in different parts of its geographic range. These
differences may be recognized by giving them a
third name, called a subspecies name. This can
be overdone, as has been the case in some groups of animals. Some people (Wilson and
Brown notably) have advocated doing away with
subspecies names, because they are usually
based on only a very small part of the variation in
the species. If a different part of the variation is
looked at it might show a very different picture
of the geographic changes in the population. This,
also, has been demonstrated.

In plants you can get forms of varieties of sub-
species, which leads to the four to six part names.
Here what is happening is that single-gene
mutations in a population are being given different
names, as though a normally red-flowered plant
were to produce an occasional white flower and it
were given a different name. This is useful only
for keeping track of horticultural varities. There is
really rarely any justification for it otherwise.

This is a question of considerably more complexity
than I have covered here. Animal classification
also sometimes went in for 4 to 6 part names, but
no more than 3 are currently accepted as valid.

Answer 3

Binomial nomenclature (genus, species) was credited to Carolus Linnaeus, a Swedish botanist.
His publication, Species plantarum (2 vol., 1753), described plants in terms of genera and species, and the 10th edition (1758) of Systema naturae applied this system to animals as well.

This type of system of classification reduced confusion due to the use of common names. Later taxa (levels) were added and later subdivisions that have arisen are such entities as Phyla (singular: phylum), Superclasses, classes, Superorders, orders, Infarorders, Families, Superfamilies, and Tribes, and varieties. This becomes polynomial, rather than just trinomial.

Perhaps you are thinking of trinomial as genus,species,variety. Any classification levels below species are considered trinomial.
Check out the links below.