The sea otter is a small mammal that lives in waters along the western coast of North America from California to Alaska.
When some sea otter populations off the Alaskan coast started rapidly declining a few years ago, it caused much concern because sea otters play an important ecological role in the coastal ecosystem. Experts started investigating the cause of the decline and quickly realized that there were two possible explanations: environmental pollution or attacks by predators.
Initially, the pollution hypothesis seemed the more likely of the two.
The first reason why pollution seemed the more likely cause was that there were known sources of it along the Alaskan coast, such as oil rigs and other sources of industrial chemical pollution. Water samples from the area revealed increased levels of chemicals that could decrease the otters' resistance to life-threatening infections and thus could indirectly cause their deaths.
Second, other sea mammals such as seals and sea lions along the Alaskan coast were also declining, indicating that whatever had endangered the otters was affecting other sea mammals as well. This fact again pointed to environmental pollution, since it usually affects the entire ecosystem rather than a single species. Only widely occurring predators, such as the orca (a large predatory whale), could have the same effect, but orcas prefer to hunt much larger prey, such as other whales.
Third, scientists believed that the pollution hypothesis could also explain the uneven pattern of otter decline: at some Alaskan locations the otter populations declined greatly, while at others they remained stable. Some experts explained these observations by suggesting that ocean currents or other environmental factors may have created uneven concentrations of pollutants along the coast.
According to what the passage expressed, sea Otters died because of pollution. In contrast, the professor said that those reasons that the passage made are weak, and Otters died because of predators.
First, as the passage expressed, increasing oil rigs and other industrial chemicals in the sea caused the Otters population to decline. However, the professor explained in the lecture if Otters died because of pollution, they must wash up on the sea, but we do not see any Otters died on the sea. In another hand, pollution had to kill other mammals, but it had not.
Second, another reason for disappearing Otters because of pollution that the passage made, is that the population of seals and sea lions were also declined. In contrast, the professor explained in the lecture that whales left the area because of a human hunter. As a result, the orca had to eat other mammals.
Third, the passage mentioned that the uneven pattern of Otters' decline is another reason for sea pollution. However, the professor said in the lecture, this uneven pattern is Because the orca is large, so it can not hunt mammals that are in shallow water, so the mammals in shallow water could survive.
Grammar and spelling errors:
Line 1, column 201, Rule ID: WHITESPACE_RULE
Message: Possible typo: you repeated a whitespace
Suggestion:
..., and Otters died because of predators. First, as the passage expressed, increas...
^^^
Transition Words or Phrases used:
also, but, first, however, if, second, so, third, in contrast, as a result
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 7.0 10.4613686534 67% => OK
Auxiliary verbs: 3.0 5.04856512141 59% => OK
Conjunction : 5.0 7.30242825607 68% => OK
Relative clauses : 7.0 12.0772626932 58% => More relative clauses wanted.
Pronoun: 13.0 22.412803532 58% => OK
Preposition: 23.0 30.3222958057 76% => OK
Nominalization: 7.0 5.01324503311 140% => OK
Performance on vocabulary words:
No of characters: 984.0 1373.03311258 72% => OK
No of words: 202.0 270.72406181 75% => More content wanted.
Chars per words: 4.87128712871 5.08290768461 96% => OK
Fourth root words length: 3.76996954942 4.04702891845 93% => OK
Word Length SD: 2.51030617543 2.5805825403 97% => OK
Unique words: 99.0 145.348785872 68% => More unique words wanted.
Unique words percentage: 0.490099009901 0.540411800872 91% => More unique words wanted or less content wanted.
syllable_count: 307.8 419.366225166 73% => OK
avg_syllables_per_word: 1.5 1.55342163355 97% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 2.0 3.25607064018 61% => OK
Article: 6.0 8.23620309051 73% => OK
Subordination: 2.0 1.25165562914 160% => OK
Conjunction: 3.0 1.51434878587 198% => OK
Preposition: 4.0 2.5761589404 155% => OK
Performance on sentences:
How many sentences: 10.0 13.0662251656 77% => Need more sentences. Double check the format of sentences, make sure there is a space between two sentences, or have enough periods. And also check the lengths of sentences, maybe they are too long.
Sentence length: 20.0 21.2450331126 94% => OK
Sentence length SD: 43.1578498074 49.2860985944 88% => OK
Chars per sentence: 98.4 110.228320801 89% => OK
Words per sentence: 20.2 21.698381199 93% => OK
Discourse Markers: 7.4 7.06452816374 105% => OK
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 1.0 4.19205298013 24% => OK
Sentences with positive sentiment : 0.0 4.33554083885 0% => More positive sentences wanted.
Sentences with negative sentiment : 4.0 4.45695364238 90% => OK
Sentences with neutral sentiment: 6.0 4.27373068433 140% => OK
What are sentences with positive/Negative/neutral sentiment?
Coherence and Cohesion:
Essay topic to essay body coherence: 0.238088565685 0.272083759551 88% => OK
Sentence topic coherence: 0.102538895091 0.0996497079465 103% => OK
Sentence topic coherence SD: 0.0730208562051 0.0662205650399 110% => OK
Paragraph topic coherence: 0.157685492534 0.162205337803 97% => OK
Paragraph topic coherence SD: 0.0343028867059 0.0443174109184 77% => OK
Essay readability:
automated_readability_index: 11.6 13.3589403974 87% => Automated_readability_index is low.
flesch_reading_ease: 59.64 53.8541721854 111% => OK
smog_index: 3.1 5.55761589404 56% => Smog_index is low.
flesch_kincaid_grade: 9.9 11.0289183223 90% => OK
coleman_liau_index: 10.97 12.2367328918 90% => OK
dale_chall_readability_score: 7.83 8.42419426049 93% => OK
difficult_words: 41.0 63.6247240618 64% => More difficult words wanted.
linsear_write_formula: 7.5 10.7273730684 70% => 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: 66.6666666667 out of 100
Scores by essay e-grader: 20.0 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.