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T
he word
cycle
means “go around.” A wheel goes around. You can
observe a wheel go through one cycle. Put a mark on a wheel.
That’s the beginning point. Turn the wheel and watch the mark
go around. When the mark comes back to the beginning point, the
wheel has completed one cycle. Another cycle is the one that happens
every day, from sunrise one day to sunrise the next day. One year is a
cycle. The Moon goes through a cycle of phases each month.
Organisms go through
life
cycles
. But an organism’s life cycle is a
little different from going around in a circle. Like all cycles, a life cycle
has a beginning, things happen, and then you find yourself back at the
beginning again.
You studied the life cycle of a bean plant. The life cycle started with
a bean seed. Inside the bean seed was the dormant embryo of a bean
plant. When the bean seed soaked up water, the seed germinated.
The bean plant started growing.
Life Cycles
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