enigma123 wrote:
Whales originated in the freshwater lakes and rivers of ancient Asia about sixty million years ago. Not until about ten million years later did species of whales develop specialized kidneys enabling them to drink salt water. Although fossil evidence shows that some early whale species that lacked such kidneys sometimes swam in the Earth’s saltwater oceans, these species must have had to return frequently to freshwater rivers to drink. Which of the following is most strongly supported by the information given?
A. Fossils of whale species dating from between sixty million and fifty million years ago will not be found on continents that were at the time separated from ancient Asia by wide expanses of ocean.
B. Among whale fossils that date from later than about fifty million years ago, none are fossils of whale species that drank only fresh water.
C. Fossils of whale species that drank fresh water will not be found in close proximity to fossils of whale species that drank salt water.
D. The earliest whales that drank salt water differed from fresh-water-drinking whales only in their possession of specialized kidneys.
E. Between sixty million and fifty million years ago, the freshwater lakes and rivers in which whales originated were gradually invaded by salt water.
Guys - any idea what the answer will be?
Quote:
My take:
Whales originated >>-where->> in ancient Asia about sixty (60 million years ago)
species of whales (Asia/which continent dont know) develop spl salt water kidneys (50 million years ago).
Although fossil evidence >>says>>> (species - kidneys) sometimes swam in the Earth’s saltwater oceans (not of Asia as Asia has fresh water), these species must have had to return (return means they travelled back) to drink.
means, kidney -minus whales of salt water (not Asia) went to freshwater (in Asia) ..this is saying that it did cross..
Why A is correct>??
I am uncertain how you arrived at the conclusions above.
Here is the explanation:
- 60 million yrs ago, whales originated in freshwater (which means lakes and rivers) of Asia
- Special kidneys that allowed whales to drink salt water evolved 50 million yrs ago.
- Sometimes whales without special kidneys swam into saltwater but they had to return frequently to freshwater.
Think about your geography - Continents are separated by huge saltwater oceans. A continent has lakes and rivers (freshwater) within it. The rivers connect to the ocean. If you want to travel from Asia to North America by water, you will need to go through the huge ocean between them.
60 million years ago, whales originated in Asia's freshwater so they were in the continent of Asia. They did not have special kidneys so they could not travel across the ocean. Even if they did enter the ocean, they needed to return back to the freshwater of Asia. Point is, they couldn't swim far from Asia. Till 50 million yrs ago, special kidneys did not develop. So for the 10 million yrs from 60 million to 50 million yrs ago, whales couldn't leave the coast of Asia and swim far. So they couldn't reach the continents far from Asia separated by saltwater oceans.
Answer (A)
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