In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.

[EX Q]: Sediment consists of _ visually distinct floc layers.
[EX A]: two

[EX Q]: Scientists use a characteristic to classify animals into _ groups.
[EX A]: two

[EX Q]: Tall fescue produces the _ diazaphenanthrene alkaloids, perlolidone and perloline.
[EX A]:
two