Electroreception - Reading Test Answers

In the third paragraph, it is stated that “However, animals with active electroreception possess bodily organs that generate special electric signals on cue. These can be used for mating signals…”. It can be concluded that the information regarding how electroreception can be used to help fish reproduce, i.e., animals with electroreception have organs that generate electric signals that help them in mating (reproduction), is given in the third paragraph of the passage. Hence, the answer is C.

In the mentioned paragraph, it is given “In areas where shark attacks on humans are likely to occur, scientists are exploring ways to create artificial electroreceptors that would disorient the sharks and repel them from swimming beaches.”. The above-mentioned sentence from Paragraph G lists that scientists can use electroreception to disorient sharks and repel them from swimming beaches, thereby benefiting humans. Hence, the answer is G.

In the specified paragraph, it is given “…some animals have the ability – known as passive electroreception – to receive and decode electric signals generated by other animals in order to sense their location.”. In other words, the second paragraph of this passage informs about the capacity which enables an animal to pick up but not send out electrical signals, which is termed as passive electroreception. Hence, the answer is B.

The first paragraph ends with the statement “This ability is only found in aquatic or amphibian species because water is an efficient conductor of electricity.”. It points out that the first paragraph tells us the reason why only creatures that live in or near water have electroreceptive abilities (water is an efficient conductor of electricity). Hence, the answer is A.

Through the last two sentences of the concluding paragraph, “Scientists are also exploring the role electroreception plays in navigation. Some have proposed that salt water and magnetic fields from the Earth’s core may interact to form electrical currents that sharks use for migratory purposes.”, it can be concluded that this paragraph refers to the ways how electroreception might help creatures find their way over long distances. Hence, the answer is H.

In the fourth paragraph, it is written “When two such electric fish meet in the ocean using the same frequency, each fish will then shift the frequency of its discharge so that they are transmitting on different frequencies. Doing so prevents their electroreception faculties from becoming jammed.”. It points out the fact that the fourth paragraph explains how some fish can avoid disrupting each other’s electric signals. Hence, the answer is D.

In Paragraph E, it is said that “Because marine life of various types is often travelling past, the embryo has evolved only to react to signals that are characteristic of the respiratory movements of potential predators such as sharks.”. This indicates that the shark’s respiratory movements alert the embryo of the young ray to its presence. Hence, the answer is ‘respiratory movements’.

The following line –The embryos keep their tails in constant motion so as to pump water and allow them to breathe through the egg’s casing.– establishes the fact that the ray embryo moves its tail in constant motion in order to breathe. Hence, the answer is ‘tail’.

In the specific line, it is mentioned that “If the embryo’s electroreceptors detect the presence of a predatory fish in the vicinity, however, the embryo stops moving (and in so doing ceases transmitting electric currents) until the fish has moved on.”. In other words, the embryo stops sending electric current when the predator (predatory fish) comes close by (in the vicinity). Hence, the answer is ‘electric current’.

In Paragraph F, it is stated that “They initially lock onto their prey through a keen sense of smell (two thirds of a shark’s brain is devoted entirely to its olfactory organs).”. From this quoted line, we can conclude that sharks use their olfactory organs, located in a specific part of their brain, to smell their target (prey). Hence, the answer is ‘olfactory organs’.

The given line specifies that “As the shark reaches proximity to its prey, it tunes into electric signals that ensure a precise strike on its target…”. It is indicated that when the shark gets close (proximity) to its prey, it uses electric signals to guide it toward an accurate attack (ensure a precise strike). Hence, the answer is ‘electric signals’.

In the quoted line, it is mentioned that “Since sharks cannot detect from electroreception whether or not something will satisfy their tastes, they tend to “try before they buy”, taking one or two bites and then assessing the results (our sinewy muscle does not compare well with plumper, softer prey such as seals).”. It can be inferred that humans are not popular food sources for most sharks due to their sinewy muscles, which make them less plump compared to soft prey like seals. Hence, the answer is ‘sinewy muscle’.

In the specified line, it is mentioned that “Repeat attacks are highly likely once a human is bleeding, however; the force of the electric field is heightened by salt in the blood which creates the perfect setting for a feeding frenzy.”. It is indicated that once a shark has bitten a human, a repeat attack is highly possible as salt from the blood increases the intensity of the electric field. Hence, the answer is ‘electric field’.