Cycles of change
A regular pattern of change is a _____.
cycle
Most nitrogen is changed into usable compounds by _____.
bacteria
Whenever an ecosystem receives less water than it needs a ____ may occur
drought
Stresses can be
either natural or manmade
Winds that change direction with the seasons and control the wet and dry seasons are ____ winds.
monsoon
Other elements need to be combined with nitrogen before it can be _____ .
used
The gradual changes in the populations of an ecosystem are called ____.
succession
A species is considered to be _____ when its last known member dies.
extinct
The energy for plants to make food comes from ____ .
the sun/ sunlight
Precipitation that soaks into the ground and is stored there is ____ .
Ground water
A______is different from other natural disasters because it does not have a definite beginning or ending.
drought
The population of an _____ species is so small that there is danger of it becoming extinct.
endangered
Animals and people breathe in oxygen and breathe out carbon dioxide during _______.
respiration
Plants release water vapor through ____.
transpiration
Another benefit of floods is that the seeds of some ______depend on annual floods so they can sprout.
trees
. An _____ species is not native to an area and can cause harm
invasive
Dead bodies break down during decomposition and release _____ into the air.
carbon dioxide
Water that falls to the earth is ____.
. precipitation
Forest fires also can recycle ____ to make the soil rich and fertile.
nutrients
Some manmade stresses are habitat destruction, _____, and excessive hunting and fishing.
pollution