Cambridge ielts 1-15 series reading answers explained

5. Answer: aggresively 
Explain 
– Key words: attacked, prey 
– Still in paragraph 4, Giraldo compared the way old and young ants attacked their prey and found that 
the old ones attacked “just as aggressively” as the young ones did. In other words, she studied how 
aggressively they attacked the prey. 
6. Answer: location 
Explain 
– Key words: comparison, age, dying, cells, brains 
– In paragraph 5, we know that Giraldo didn‟t find any major difference in age and the location of 
dying brain cells between 20-day-old and 95-day-old ants. This suggests that she compared between 
the age and location of dying cells. 
7. Answer: neurons 
Explain 
– Key words: synaptic, complexes, brain‟s, mushroom bodies 

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– In paragraph 5, it is stated that synaptic complexes are “regions where 
neurons come together” 
8. Answer: chemicals 
Explain 
– Key words: two, brain, associated, ageing 
– Still in paragraph 5, we are told that Giraldo studied the level of serotonin and dopamine, which are 
two “brain chemicals whose decline often coincides with aging”. This implies that they are associated 
with aging. Thus, the answer is “chemicals”. 
9. Answer: FALSE 
Explain 
– Key words: Pheidole dentata remain, active, whole, life 
– In paragraph 2, the author mentions naked mole rats as an age-defying 
animal: they stay fit for nearly their entire lives and they can reproduce even when old. It can be said 
that they remain active for almost their whole life. Thus, Pheidole dentata ants are not the only animal 
with this feature. 
10. Answer: TRUE 
Explain 
– Key words: Ysabel Giraldo, first, Pheidole dentata precise, data, age 
– It is stated in paragraph 3: “Unlike all previous studies, which only estimated how old the ants 
were…she knew their exact ages”. This means that she was the first person to use the ants‟ exact ages 
in her studies.