instruction:
In this task, you are given a paragraph, and your job is to generate comma-separated entities present in the given paragraph. Generate entities from a given passage in such a way that (i) they are present in the paragraph, (ii) they are non-duplicate, (iii) they underwent a state change during the process. Avoid creating entities that (i) aren't present in the process paragraph and (ii) aren't significant.
question:
A sperm and egg meet inside a woman's fallopian tube. The fertilized egg, now a zygote, travels to the uterus. The zygote implants in the uterus. The zygote becomes an embryo. The embryo becomes a fetus. The fetus grows for approximately 9 months. The woman gives birth to a baby. The baby grows into a child. The child becomes an adult. The adult mates with another adult.
answer:
sperm ,egg ,fertilized egg; zygote ,embryo ,fetus ,baby ,child ,adult

question:
Electrical signals in the brain travel through nerves to muscles. Two types of proteins exist in filaments in the muscles. The filaments move when the brain instructs them to. The motion of the filaments cause the muscle to shorten and contract. Opposing pairs of muscles exist in order to provide the necessary range of motion.
answer:
electrical signals ,proteins ,filaments

question:
Water in the clouds becomes very cold. The cold water forms ice crystals. The ice crystals grow by absorbing surrounding water droplets. Form snowflakes. The snowflakes fall to the ground.
answer:
water ,ice crystals ,snowflakes