Scientists are considering the possibility of sending humans to Mars in the coming decades. Although there have been successful manned missions to the Moon in the 1960s and 1970s, Mars is 150 times further away from Earth than the Moon is. Thus the project of sending humans to Mars would require solving an array of problems the Moon missions did not have to face.
One problem is that a round-trip to Mars and back is likely to take at least two years. The trip to the Moon lasted only a few days, and it was easy to bring enough supplies of food, water, and oxygen; but the cargo capacity of space vehicles is too limited to put on board the food, water, and oxygen required by a crew for a period of two years. Without those essentials, though, a Mars mission is impossible.
A second problem is that astronauts on the Mars mission would be in the zero-gravity environment of space for many months at a time. Spending a long time in the zero-gravity environment has negative effects on the human body, such as decreased muscle mass and lower bone density. Over the course of a two-year mission, the effects would be so severe, they would make it impossible for humans to make the trip without experiencing grave medical problems.
Finally, astronauts on a mission to Mars would be exposed to dangerous levels of space radiation, much of which comes in the form of charged particles emitted by the Sun. Earth's magnetic field, which normally protects us from dangerous solar radiation, would not be able to protect a spaceship traveling in interplanetary space. Constructing a shield that would protect the whole spaceship from space radiation is at present impossible because it would add too much weight to the ship.
- At the end of the Triassic period 200 million years ago, there was a mass-extinction event that caused the extinction of more than half of all living species. It was this extinction event that allowed dinosaurs to become the dominant species for the next 80
- Like many creatures, humpback whales migrate long distances for feeding and mating purposes. How animals manage to migrate long distances is often puzzling. In the case of humpback whales, we may have found the answer: they may be navigating by the stars, 76
- Many scientists believe it would be possible to maintain a permanent human presence on Mars or the Moon. On the other hand, conditions on Venus are so extreme and inhospitable that maintaining a human presence there would be impossible. First, atmospheric 3
- Summarize the points made in the lecture you just heard, explaining how they cast doubt on points made in the reading.In the United States, it had been common practice since the late 1960s not to suppress natural forest fires. The “let it burn” policy 3
- In the United States, it had been common practice since the late 1960s not to suppress natural forest fires. The “let it burn” policy assumed that forest fires would burn themselves out quickly, without causing much damage. However, in the summer of 1 60
Grammar and spelling errors:
Line 1, column 241, Rule ID: SENT_START_CONJUNCTIVE_LINKING_ADVERB_COMMA[1]
Message: Did you forget a comma after a conjunctive/linking adverb?
Suggestion: Thus,
...rther away from Earth than the Moon is. Thus the project of sending humans to Mars w...
^^^^
Transition Words or Phrases used:
but, finally, second, so, thus, at least, such as
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 15.0 10.4613686534 143% => OK
Auxiliary verbs: 8.0 5.04856512141 158% => OK
Conjunction : 7.0 7.30242825607 96% => OK
Relative clauses : 5.0 12.0772626932 41% => More relative clauses wanted.
Pronoun: 9.0 22.412803532 40% => OK
Preposition: 49.0 30.3222958057 162% => OK
Nominalization: 5.0 5.01324503311 100% => OK
Performance on vocabulary words:
No of characters: 1431.0 1373.03311258 104% => OK
No of words: 299.0 270.72406181 110% => OK
Chars per words: 4.78595317726 5.08290768461 94% => OK
Fourth root words length: 4.1583189471 4.04702891845 103% => OK
Word Length SD: 2.64302089391 2.5805825403 102% => OK
Unique words: 164.0 145.348785872 113% => OK
Unique words percentage: 0.548494983278 0.540411800872 101% => OK
syllable_count: 432.9 419.366225166 103% => OK
avg_syllables_per_word: 1.4 1.55342163355 90% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 1.0 3.25607064018 31% => OK
Article: 4.0 8.23620309051 49% => OK
Subordination: 1.0 1.25165562914 80% => OK
Conjunction: 4.0 1.51434878587 264% => Less conjunction wanted as sentence beginning.
Preposition: 2.0 2.5761589404 78% => OK
Performance on sentences:
How many sentences: 12.0 13.0662251656 92% => OK
Sentence length: 24.0 21.2450331126 113% => OK
Sentence length SD: 48.4352374024 49.2860985944 98% => OK
Chars per sentence: 119.25 110.228320801 108% => OK
Words per sentence: 24.9166666667 21.698381199 115% => OK
Discourse Markers: 4.08333333333 7.06452816374 58% => More transition words/phrases wanted.
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 1.0 4.19205298013 24% => OK
Sentences with positive sentiment : 3.0 4.33554083885 69% => OK
Sentences with negative sentiment : 7.0 4.45695364238 157% => OK
Sentences with neutral sentiment: 2.0 4.27373068433 47% => OK
What are sentences with positive/Negative/neutral sentiment?
Coherence and Cohesion:
Essay topic to essay body coherence: 0.377679902007 0.272083759551 139% => OK
Sentence topic coherence: 0.161989837922 0.0996497079465 163% => OK
Sentence topic coherence SD: 0.208909405831 0.0662205650399 315% => The coherence between sentences is low.
Paragraph topic coherence: 0.262371524296 0.162205337803 162% => OK
Paragraph topic coherence SD: 0.316241648692 0.0443174109184 714% => More connections among paragraphs wanted.
Essay readability:
automated_readability_index: 13.6 13.3589403974 102% => OK
flesch_reading_ease: 64.04 53.8541721854 119% => OK
smog_index: 8.8 5.55761589404 158% => OK
flesch_kincaid_grade: 10.3 11.0289183223 93% => OK
coleman_liau_index: 10.8 12.2367328918 88% => OK
dale_chall_readability_score: 8.42 8.42419426049 100% => OK
difficult_words: 68.0 63.6247240618 107% => OK
linsear_write_formula: 10.5 10.7273730684 98% => OK
gunning_fog: 11.6 10.498013245 110% => OK
text_standard: 11.0 11.2008830022 98% => OK
What are above readability scores?
---------------------
Rates: 80.0 out of 100
Scores by essay e-grader: 24.0 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.