sabre-toothed cats, cave bears, giant deer, etc..
Answer: Valves in the veins
Explanation: The flow of the blood inside the body takes place through the veins and arteries. The oxygenated blood from the heart is supplied to the different parts of the body.
The blood flows from the capillaries to the venules and from there to the veins. The blood moves in the veins by the rhythmic movement of the smooth muscles in the body.
Most of the blood moves against the gravity so there is a chance that it can backflow so to prevent this there are valves in the veins known as one way valves.
Both the temperate grasslands and temperate forests experience <u>seasonal climatic changes </u>
Explanation:
Both the temperate grasslands and temperate forests experience experience all the four seasons - spring, summer, winter and fall.
These climatic changes can be observed throughout the year with summer being warm and dry and winter being very cold. The summer temperature averages around 21 degrees centigrade while the winter temperature can go down below freezing levels.
This extremely cold winter leads to shedding of leaves of deciduous trees found in the temperate forests. The grasses in the temperate grasslands also shed and die annually with the roots and new buds protected by the soil during the cold weather.
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