Which type of snake uses both serpentine and concertina forms of movement? A. python
B. rat
C. boa
D. grass

It is one of at least five forms of locomotion used by snakes, the others being lateral undulation, sidewinding, concertina movement, and slide-pushing. Unlike all other modes of snake locomotion, which include the snake bending its body, the snake flexes its body only when turning in rectilinear locomotion.

in this passage from chapter 6 of "animal farm", by george orwell, what the author is ridiculing in this passage is the frivolity of some rules.

clover, the mare, believes she remembers that the fourth commandment forbade sleeping in beds because it was something that humans did. snowball, napoleon, and the pigs are brain-workers who look after the welfare of the farm. they are the obvious leaders because they are smart, and so they are entitled to eat the best food and sleep in beds. it is squealer, who says these lines making the difference between sleeping with sheets, what humans do, and sleeping in beds, what pigs do. the unwillingness to question authority makes the oppressed to obey without thinking.