A huge marine mammal known as Steller's sea cow once lived in the waters around Bering Island off the coast of Siberia. It was described in 1741 by Georg W. Steller, a naturalist who was among the first Europeans to see one. In 1768 the animal became extinct. The reasons for the extinction are not clear. Here are three theories about the main cause of the extinction.
First, the sea cows may have been overhunted by groups of native Siberian people. If this theory is correct, then the sea cow population would have originally been quite large, but hundreds of years of too much hunting by the native people diminished the number of sea cows. Sea cows were a good source of food in a harsh environment, so overhunting by native people could have been the main cause of extinction.
Second, the sea cow population may have become extinct because of ecosystem disturbances that caused a decline in their main source of food, kelp (a type of sea plant). Kelp populations respond negatively to a number of ecological changes. It is possible that ecological changes near Bering Island some time before 1768 caused a decrease of the kelp that the sea cows depended on.
Third, the main cause of extinction of the sea cows could have been European fur traders who came to the island after 1741. It is recorded that the fur traders caught the last sea cow in 1768. It thus seems reasonable to believe that hunting by European fur traders, who possessed weapons that allowed them to quickly kill a large number of the animals, was the main cause of the sea cow's extinction.
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Grammar and spelling errors:
Line 5, column 483, Rule ID: POSSESIVE_APOSTROPHE[2]
Message: Possible typo: apostrophe is missing. Did you mean 'cows'' or 'cow's'?
Suggestion: cows'; cow's
...eriod, and that did not bring about sea cows disappearance. Finally, the author d...
^^^^
Line 7, column 99, Rule ID: POSSESIVE_APOSTROPHE[2]
Message: Possible typo: apostrophe is missing. Did you mean 'cows'' or 'cow's'?
Suggestion: cows'; cow's
... entered the island resulted in the sea cows elimination. However, the professor rep...
^^^^
Transition Words or Phrases used:
finally, first, hence, however, if, nevertheless, nonetheless, second, so, still, therefore, well, while, such as
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 13.0 10.4613686534 124% => OK
Auxiliary verbs: 4.0 5.04856512141 79% => OK
Conjunction : 3.0 7.30242825607 41% => More conjunction wanted.
Relative clauses : 16.0 12.0772626932 132% => OK
Pronoun: 23.0 22.412803532 103% => OK
Preposition: 25.0 30.3222958057 82% => OK
Nominalization: 14.0 5.01324503311 279% => Less nominalizations (nouns with a suffix like: tion ment ence ance) wanted.
Performance on vocabulary words:
No of characters: 1453.0 1373.03311258 106% => OK
No of words: 272.0 270.72406181 100% => OK
Chars per words: 5.34191176471 5.08290768461 105% => OK
Fourth root words length: 4.06108636974 4.04702891845 100% => OK
Word Length SD: 2.76270803519 2.5805825403 107% => OK
Unique words: 159.0 145.348785872 109% => OK
Unique words percentage: 0.584558823529 0.540411800872 108% => OK
syllable_count: 445.5 419.366225166 106% => OK
avg_syllables_per_word: 1.6 1.55342163355 103% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 4.0 3.25607064018 123% => OK
Article: 7.0 8.23620309051 85% => OK
Subordination: 1.0 1.25165562914 80% => OK
Conjunction: 1.0 1.51434878587 66% => OK
Preposition: 1.0 2.5761589404 39% => More preposition wanted as sentence beginning.
Performance on sentences:
How many sentences: 13.0 13.0662251656 99% => OK
Sentence length: 20.0 21.2450331126 94% => OK
Sentence length SD: 30.798447667 49.2860985944 62% => OK
Chars per sentence: 111.769230769 110.228320801 101% => OK
Words per sentence: 20.9230769231 21.698381199 96% => OK
Discourse Markers: 8.69230769231 7.06452816374 123% => OK
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 2.0 4.19205298013 48% => OK
Sentences with positive sentiment : 1.0 4.33554083885 23% => More positive sentences wanted.
Sentences with negative sentiment : 4.0 4.45695364238 90% => OK
Sentences with neutral sentiment: 8.0 4.27373068433 187% => OK
What are sentences with positive/Negative/neutral sentiment?
Coherence and Cohesion:
Essay topic to essay body coherence: 0.183521013278 0.272083759551 67% => OK
Sentence topic coherence: 0.0664051895626 0.0996497079465 67% => OK
Sentence topic coherence SD: 0.0677297415933 0.0662205650399 102% => OK
Paragraph topic coherence: 0.115911711947 0.162205337803 71% => OK
Paragraph topic coherence SD: 0.0442006731689 0.0443174109184 100% => OK
Essay readability:
automated_readability_index: 14.2 13.3589403974 106% => OK
flesch_reading_ease: 51.18 53.8541721854 95% => OK
smog_index: 8.8 5.55761589404 158% => OK
flesch_kincaid_grade: 11.1 11.0289183223 101% => OK
coleman_liau_index: 13.69 12.2367328918 112% => OK
dale_chall_readability_score: 9.33 8.42419426049 111% => OK
difficult_words: 81.0 63.6247240618 127% => OK
linsear_write_formula: 14.5 10.7273730684 135% => OK
gunning_fog: 10.0 10.498013245 95% => OK
text_standard: 10.0 11.2008830022 89% => OK
What are above readability scores?
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Rates: 86.6666666667 out of 100
Scores by essay e-grader: 26.0 Out of 30
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Note: the e-grader does NOT examine the meaning of words and ideas. VIP users will receive further evaluations by advanced module of e-grader and human graders.