What is thesaurus and online resources?

thesaurus is a book that is filled with all types of synonyms for words

synonyms are words that are different but same in meaning

eg: yummy

another word for yummy is delicious

so delicious is a synonym that is included in the book named thesaurus

hope it helps

; )

Explanation:

the oldest known insects are believed to live around 400 millions ago as suggested by the fossil records.   some plants having woody stems also evolved during this time.

after the evolution of insects the first four legged species or the tetrapods evolved in shallow freshwater habitats from the intermediate species approximately 397 million years ago. the tetrapods went on conquering the land giving rise to amphibians, reptiles, mammals and birds.

the major split in tetrapods first occurred 340 million years ago branching off from amphibians.

363 million years ago when the carboniferous period began the insects started roaming on land and taking flights, following which the four limbed tetrapods adapted in the terrestrial habitat.