D Mountain hope this helps
Circulatory system.....circulates blood (a vital delivery system of oxygen) throughout the whole body when tissues need it the most and with a constant supply.
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Amid the Ordovician Period, the outside of the earth was drastically unique in relation to it is today. About all life on earth was in the seas. The main land life was as exceptionally crude plants extremely close to the water line of the coasts, presumably greeneries and green growth and were of a non-vascular nature.
The Ordovician Period started with a noteworthy eradication called the Cambrian– Ordovician annihilation occasion, about 485.4 Mya (million years prior). It went on for around 42 million years and finished with the Ordovician– Silurian elimination occasions, about 443.8 Mya (ICS, 2004) which cleared out 60% of marine genera.
The timeframe that occurred 488 to 443 million years back. Amid the Ordovician time frame, some portion of the Paleozoic time, a rich assortment of marine life thrived in the tremendous oceans and the primary crude plants started to show up ashore—before the second biggest mass annihilation ever finished the period.
Fish don't have ears we can see but they have ear parts inside their heads. They pick up sounds in water through their bodies.
