In biological classification, class () is:

The composition of each class is determined by a taxonomist. Often there is no exact agreement, with different taxonomists taking different positions. There are no hard rules that a taxonomist needs to follow in describing a class, but for well-known animals there is likely to be consensus.

In botany, classes are now rarely discussed. Since the first publication of the APG system in 1998, which proposed a taxonomy of the flowering plants up to the level of orders, many sources have preferred to treat ranks higher than orders as informal clades. Where formal ranks have been assigned, the ranks have been reduced to a very much lower level, e.g. class Equisitopsida for the land plants, with the major divisions within the class assigned to subclasses and superorders.

For some clades, a number of alternative classifications are used.

The class as a distinct rank of biological classification having its own distinctive name (and not just called a "top-level genus" "(genus summum)" was first introduced by the French botanist Joseph Pitton de Tournefort in his classification of plants that appeared in his "Elements de botanique", 1694.

In the first edition of his "Systema Naturae" (1735). Carl Linnaeus divided all three of his kingdoms of Nature (minerals, plants, and animals) into classes. Only in the animal kingdom are Linnaeus's classes similar to the classes used today; his classes and orders of plants were never intended to represent natural groups, but rather to provide a convenient "artificial key" according to his "Systema Sexuale", largely based on the arrangement of flowers.

Now, provide a numbered list of answers to these questions:

1. Who published about nature in the 18th century?
2. what year was the 1st edition published?
3. the name of the book?
4. how many kingdoms did he have?
5. name one
6. another?
7. and?
8. what were each divided into
9. are they all used today?
10. are any?
11. what's the class determined by?
12. do they agree?
13. are there strict rules?
14. when did Joseph Pitton de Tourefort publish his work?
15. it's name?
16. his nationalist?
17. what was published in 1998?
18. are classes discussed in plant study now?
19. what did the APG suggest?
20. what did Linnaeus mean his plant classes to be?
1. Carl Linnaeus
2. (1735).
3. "Systema Naturae"
4. three
5. minerals
6. plants
7. and animals
8. into classes
9. no
10. Only in the animal kingdom are Linnaeus's classes similar to the classes used today
11. class is determined by a taxonomist
12. no
13. no
14. 1694
15. "Elements de botanique"
16. French
17. the APG system
18. rarely
19. it proposed a taxonomy of the flowering plants up to the level of orders
20. a convenient "artificial key