Given a scientific question, generate a correct answer to it.

[EX Q]: Two kinds of sex hormones are of particular importance in females: progesterone, which prepares the uterus for pregnancy and prevents the further release of eggs from the ovaries during pregnancy, and the estrogens, which are mainly responsible for the development of female secondary sexual characteristics, such as breast development and increased deposition of this?
[EX A]: fat

[EX Q]: Chewing a bite of bread mixes it with what and facilitates its chemical breakdown?
[EX A]: saliva

[EX Q]: What takes both the shape and the volume of their container?
[EX A]:
gases