(C) is the correct answer.
It is the correct answer because it is closest in meaning to the word evolution.

The key to answering this question is to highlight the word in the sentence and clarify its meaning and part of speech.
It is believed that eyes evolved over a few million years during the Cambrian explosion, a rapid period of evolution.
Evolution is the noun form of evolve, which means change and develop. Eyes changed and developed over millions of years. Therefore, answer C is correct.

(A) is incorrect because this word means mutation in habits and activities. The text refers to changes in a physical organ, not habits or activities.

(B) is not the correct answer because the paragraph is not referring to changes in habits and behaviours, but to eyes.

(D) is not the correct answer because the author is writing about the evolution of eyes in both animals and humans.

(B) is the correct answer.
It is the correct answer because there is evidence to support this statement in paragraph 1.
The key to answering this question correctly is to find the general meaning of the text that refers to the Cambrian Explosion. Find the referral in the text and underline key ideas around it:
Eyes seem to have evolved over a few million years during the Cambrian explosion, a rapid period of evolution . Prior to this time, there is no direct evidence of eyes.

We can safely conclude that before (prior to) the Cambrian Explosion, eyes did not exist – Answer (B).

(A) is incorrect because it blatantly contradicts the first two sentences of paragraph 1.

(C) is not the correct answer because it contradicts the point that eyes did not exist prior to the Cambrian Explosion, so visual acuity is not relevant.

(D) is the wrong answer because again, it contradicts the point that eyes did not exist prior to the Cambrian Explosion, so the ability to identify motion, color or light is not relevant.

(B) is the correct answer.
It is the correct answer because it explains the purpose of the reference to the book.
The key to answering the question is to discover the general meaning of the paragraph and then, to connect the reference to Darwin’s book to this meaning.
When we identify the sentence mentioning On Origin of the Species, we read that Darwin’s suggestions about the evolution of the eye were validated by modern scientists. Therefore, answer (B) is the correct one.

(A) is not the correct answer because there it contradicts line 8 of paragraph 2, Current research validates the theory of Darwin.

(C) is not the correct answer because there is no reference in the paragraph that Darwin was the first researcher in eye evolution.

(D) is wrong because it makes a false statement from the paragraph that Darwin's On Origin of the Species is a book about the evolution of eyes. It is, in fact, a book about evolution.

(A) is the correct answer because there is evidence to support this statement in paragraph 3:

The key to answering the question successfully is to identify the sentence in the text that refers to the development o a fully function vertebrate eye Then, highlight the sentences describing this development and match this description (with matching synonyms and words) with the right answer.

The development of the circular patch of photoreceptor cells into a fully functional vertebrate eye has been estimated on rates of mutation, relative benefit to the organism, and natural selection.

Take a look at the synonyms between the statement from the paragraph and the correct answer:
Guessed = Estimated
Benefit = advantage

(B) is not the correct answer because although fossils are mentioned in the paragraph, they are not connected to estimation of the development of a fully functional vertebrate eye.

(C) is not the correct answer because the statement is limited. The development of a fully functional vertebrate eye been estimated not only on natural selection, but also on rates of mutation and advantages to the organism.

(D) is not the correct answer because again, even though fossils are referred to in the paragraph, they are not connected to the estimation of the development of a fully functional vertebrate eye.

(A) is the correct answer because it is closest in meaning to the word validates.

The key to answering this question is to highlight the word in the sentence and clarify its meaning in the greater context of the passage. We learn from the text that modern science has validated – and therefore confirmed, proven – the work of Darwin.

(B) is incorrect as word means makes negative. This word is the antonym of the sample word from the passage.
(C) is not the correct answer because this word means inverts.
(D) is wrong because this word means queries.

(A) is the correct answer because it is closest in meaning to the word estimated.

The key to answering this question is to highlight the word in the sentence and clarify its meaning in the greater context of the passage. When we read the sentences about the development of cells into an eye, we learn that it is suggested that it would take less than 364,000 years for the complete evolution of the eye.
We understand that making an estimate leads to a suggestion. Therefore, it is a guess, hypothesis and not proven. Hence, answer A is correct.

(B) is wrong because this word means verified or proven.
(C) is not correct because this word means explored.
(D) is the incorrect answer because this word means confirmed, validated.

(C) is the correct answer.
It is correct because this sentence changes the statement, 96% of species have a more complex optical system that allows light discrimination within a few degrees.
To answer the question successfully, read the answers carefully and remember that you are looking for the false statement. Then, scan paragraph 4 and highlight the matching information that correspond to the true answers. Answer C is the only false statement.
A, B and D are all found in the text.

(A) The fundamental light-processing unit of the eye is the photoreceptor cell, a specialized cell with two types of molecules in its membrane: the opsin, a light-sensitive protein, and the chromophore – a pigment that can distinguish colors – which it surrounds.

(B) This group of cells is called an ‘eyespot’.

(D) However, 96% of species have a more complex optical system that allows light discrimination within a few degrees.

(B) is the correct answer.
It is the correct answer because it’s closest in meaning to the word transmit.

The technique in answering this question is to highlight the word in the sentence and clarify its meaning in the greater context of the passage. We read in the paragraph that there is a connection between the eyes and the muscles. Therefore, a message is sent or transmitted. Hence, answer (B) is the correct one.
Their eyes transmit a message directly to the muscles without the intermediate processing provided by a brain.

(A) is wrong because this word means aim or target.
(C) is not the correct answer because this word means build. This word doesn’t make sense in this sentence.
(D) is incorrect because this word means validate or confirm.

(C) is the correct answer.
It is the correct answer because there is evidence to support this statement in paragraph 6:

The trick in answering the question is to find supporting reference in the paragraph for one statement in the list of answers that relates to the words marine mollusc. Highlight this word and read around it to find information:
With a reduced size of the opening, organisms achieved true imaging, allowing for finer sensing of direction and shape. The nautilus, a marine mollusc, has this type of opening.
We see the second sentence gives the marine mollusc as an example of an organism with a reduced-size opening – answer (C) is correct.

(A) is wrong because it refers to a large rather than a reduced opening, thus contradicting the true information in the paragraph.

(B) is not the correct answer because it refers to a larger light opening rather than a reduced opening.

(D) is incorrect as it contradicts the correct meaning of sentences 6 to 8 that in fact, the light opening in the marine mollusc are still a major evolution from the earlier eye patches.

(C) is the correct answer.
It is the correct answer because it’s closest in meaning to the word spectrum.

The key to answering this question is to highlight the word in the sentence and clarify its meaning in the greater context of the passage. The paragraph speaks about light colors. Therefore, we know the word spectrum relates to the color spectrum or band. (C) is the correct answer.

So, why is it that eyes specialize in detecting a specific, narrow range of wavelengths on the electromagnetic spectrum —the visible spectrum? It is probably because the earliest species to develop photosensitivity were aquatic (such as jellyfish), and only two specific wavelength ranges of electromagnetic radiation, blue and green visible light, can be transmitted through water. This same light-filtering property of water also influenced the photosensitivity of plants.

(A) is wrong because this word means without light. This couldn’t make sense in this paragraph as it refers to both color and light.

(B) is not correct because this word means arc of light and the text refers to not only light, but to color too.

(D) is incorrect because this word refers to a special type of light that the text never mentions.

(A) is the correct answer because it follows what the passage states that the optical system started out as cells grouped into eye patches and then developed into cups.
The strategy in answering this question accurately is to highlight the key words in the sentence, clarify the general meaning and then match both to the correct answer.
Let’s look at the synonyms between the statement from the text and the first answer:
Began = started out
Multi-cellular eye patches = Cells grouped into eye patches
Gradually evolved = developed over time
Therefore, (A) is the right answer.

(B) is incorrect because it inverts the meaning of the original sentence.

(C) is not the correct answer because the eye patches were not grouped into cells, the cells were grouped into eye patches.

(D) is wrong because as there is no reference that these systems evolved into cells (They started as cells).

(C) is the correct answer because it is inferred in the passage through references the evolution of eyes during the Cambrian Explosion.

The strategy in answering this question correctly is to read through the answers and highlight key words that match the reference to the evolution of eyes during this era. In each paragraph, there are many references to the development of eyes over a few million years during the Cambrian Explosion. We can now perfectly assume that (C) is the correct answer.

Eyes seem to have evolved over a few million years during the Cambrian explosion, a rapid period of evolution...
During the Cambrian explosion, evolution of the eye was very fast, with dramatic developments in image-processing and light direction detection.

(A) is not the correct answer because within a few thousand years should be over a few million years.

(B) is incorrect as it refers to prior, not during the Cambrian Explosion.

(D) is not the correct answer because it refers to after, not during the Cambrian Explosion.

(D) is correct because the sample sentence should following the preceding sentence describing the theory of Darwin.

The technique in answering the question is to identify the part of speech of the word This.
A demonstrative adjective, This is replacing the subject noun. From the sentence, we know it is something proposed by modern scientists. As we read through the paragraph, we understand This is referring to the idea that current research validates Darwin’s theory. Hence, the sentence must be placed at (D).

(A), (B) and (D) are all incorrect as the sentence would be illogical if placed at these points.