Observation of life i think
A quatrain is a verse with four lines, or even a full poem containing four lines, having an independent and separate theme. Often one line consists of alternating rhyme,
existing in a variety of forms. We can trace back quatrains in poetic
traditions of various ancient civilizations, such as China, Ancient
Rome, and Ancient Greece; and they continue to appear in the
twenty-first century.
Counterbalanced designs allow the researcher to isolate the main effects due to condition and control for order and sequence effects only if there is no interaction between the procedural variables and the independent variables.
Answer:
Treehouses can make special and unique houses. Treehouses are really hard to build and maintain.
Explanation: