Answer:
A:
1) Heptathlon: Hepta = seven
2) Octameter: octa = eight (the poem has an 8 meter rhythm)
3) Octopus: only water animal in the list
4) Octave: octa=eight (the musicians went 8 notes higher to match the singer's range)
5) a.septuagenarian: septa = seven (she is in her seventies)
b. octogenarian: octa = eight (she will be in her eighties)
6) a. octagon: octa = eight and gon = sides (eight sided)
b. septagon: septa = seven and gon = sides (seven sides)
B:
1) The stop sign is an octagon.
2) Many people at nursing homes are either septuagenarians or octogenarians and need help with daily tasks.
C:
1) octave (8 note scale)
2) heptathlon (7 part event)
3) Octagon (8 sided shape)
4) Septagon (7 sided shape)