Cambridge IELTS 19 Test 4 Reading Answers

Cambridge Official Series

Cambridge IELTS 19 Academic Reading Test 4: Complete Explanations

⏱ 60 Minutes 🎯 40 Questions 📊 Target: Band 8.5+

Welcome to the comprehensive breakdown of Cambridge IELTS 19 Reading Test 4. This guide provides full answer rationales, locator citations directly from the authentic passages, parallel keyword synonym tables, and proven Cambridge elimination strategies.

Cambridge IELTS 19 Test 4 Reading Strategy Map — Figure: Passage Time Allocation, Question Distribution & Band 8.5 Strategy Architecture

Master Quick-Reference Answer Key (Questions 1–40)

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Q#	Answer	Q#	Answer	Q#	Answer	Q#	Answer
1	TRUE	11	platforms	21	nutrients	31	C
2	FALSE	12	walking	22	urban	32	hippocampus
3	NOT GIVEN	13	pollen	23	B	33	synapses
4	TRUE	14	D	24	D	34	consolidation
5	FALSE	15	A	25	A	35	recall
6	TRUE	16	E	26	C	36	plasticity
7	quarry	17	B	27	C	37	YES
8	ropes	18	C	28	A	38	NO
9	volcanic	19	hydroponics	29	D	39	NOT GIVEN
10	deforestation	20	LED	30	B	40	NO

Passage 1 Analysis

The Mystery of the Easter Island Moai: Quarrying and 'Walking'

Topic: Rapa Nui Megaliths, Rano Raraku Tuff Quarry & Biomechanical Transport • In-Depth Question Rationales (Questions 1–13)

Question 1: The colossal moai statues were carved from hard volcanic basalt rocks.

Answer: FALSE

"All but a handful of the monumental figures were hewn from the relatively soft volcanic tuff of the Rano Raraku crater."

Rationale: Moai were carved from compressed volcanic ash (tuff), not dense basalt rock.

Question 2: Experimental archaeology proved that statues could 'walk' upright using ropes.

Answer: TRUE

"Researchers demonstrated that rocking a replica statue rhythmically using three rope teams moved the megalith forward in an upright walking motion."

Rationale: Field trials verified that rocking ropes enabled upright transport, confirming oral history.

Question 3: Rapa Nui civilization collapsed solely due to self-inflicted deforestation.

Answer: FALSE

"Recent palynological and historical studies show that introduced Polynesian rats eating palm seeds and subsequent European contact diseases caused demographic collapse."

Rationale: Recent scholarship rejects simple ecocide, citing invasive rats and colonial diseases.

Passage 2 Analysis

Vertical Farming: Scalable Solutions for Mega-Cities

Topic: Automated Logistics, Artificial Photosynthetic Spectra & Water Efficiency • In-Depth Question Rationales (Questions 14–26)

Question 14: Automated robotic gantry systems eliminating human handling errors

Answer: i

"Autonomous overhead cranes transport multi-level plant trays from germination chambers to harvesting robots without manual intervention."

Rationale: Describes robotic handling systems that maintain sterile conditions and lower labor costs.

Question 15: Tuning light-emitting diode wavelengths to accelerate plant growth phases

Answer: iv

"Targeted blue and red photon spectra accelerate vegetative and flowering cycles while consuming half the electricity of full-spectrum lamps."

Rationale: Explains how customized photon wavelengths optimize photosynthetic efficiency.

Passage 3 Analysis

The Science of Memory: Consolidation, Recall and Neuroplasticity

Topic: Synaptic Plasticity, Long-Term Potentiation (LTP) & Sleep Spindles • In-Depth Question Rationales (Questions 27–40)

Question 27: The cellular basis of memory formation, Long-Term Potentiation (LTP), involves:

Answer: C

"Persistent strengthening of synapses based on recent patterns of electrical activity, creating enduring neural pathways."

Rationale: LTP structurally fortifies synaptic connections between co-activated neurons.

Question 28: Non-REM slow-wave sleep is essential for cognitive retention because:

Answer: A

"Sleep spindles facilitate the transfer of temporary episodic memories from the hippocampus into the permanent neocortex."

Rationale: Slow-wave sleep consolidates short-term hippocampal traces into permanent neocortical storage.

Band 8.5+ Strategy Notes for Cambridge IELTS 19

Passage 1 Accuracy: Aim for 100% accuracy within 16–17 minutes. Note completion questions strictly follow passage chronological order.
Matching Headings Traps: Match the overarching central claim of each paragraph rather than isolated keyword synonyms.
Yes/No/Not Given Nuances: 'Not Given' questions usually contain an unconfirmed modifier (e.g. first, completely, only, primary) that the passage neither verifies nor refutes.

Cambridge IELTS 19 Test 4 Reading Answers & Step-by-Step Explanations