Meaning: In this context, 'dream' refers to an idea or concept that is highly desired but was previously thought to be impossible or unrealistic.

Wrong options:

• dream: N/A
• tangible: The word 'tangible' means something that can be touched or physically felt, which does not fit the context of something that was hard to imagine.
• mundane: The term 'mundane' refers to something ordinary or commonplace, which contradicts the notion of advanced capabilities that were hard to envision.
• obsolete: 'Obsolete' means something that is no longer in use or outdated, which does not align with the idea of imagining future possibilities.

Correct answer: open source

Explanation: The term 'open source' is appropriate as it describes software that is publicly accessible and modifiable, which is crucial for developers to create diverse applications. This fits grammatically and contextually within the sentence, emphasizing the role of flexibility in smartphone evolution.

Meaning: 'Open source' refers to software that allows users to view, modify, and distribute its source code, fostering innovation and collaboration among developers.

Wrong options:

• modular: 'Modular' refers to a design that is composed of separate components, which does not specifically address the accessibility and flexibility needed for application development.
• proprietary: 'Proprietary' means owned by a specific company and not available for public modification, which contradicts the idea of enabling widespread development.
• static: 'Static' implies something that is fixed or unchanging, which does not align with the dynamic nature of application development in smartphones.

Correct answer: wireless charging

Explanation: The phrase 'wireless charging' fits grammatically as a noun phrase that describes a technology that allows devices to charge without physical connectors. Contextually, it aligns with advancements that enhance connectivity and usability in smartphones.

Meaning: 'Wireless charging' refers to the technology that allows electronic devices to be charged without the need for physical cables, using electromagnetic fields to transfer energy.

Wrong options:

• biometric scanning: 'Biometric scanning' refers to technology that uses unique physical characteristics for identification, which does not directly relate to connectivity improvements.
• satellite: 'Satellite' refers to technology used for communication and navigation, but it does not specifically address the charging capabilities of smartphones.
• Bluetooth: 'Bluetooth' is a wireless technology for data exchange over short distances, which is not relevant to the context of charging technology.

Correct answer: augmented reality

Explanation: The term 'augmented reality' fits grammatically and contextually as it describes technology that overlays digital information onto the real world, which aligns with the idea of enhancing smartphone capabilities and blurring digital and physical realms.

Meaning: 'Augmented reality' refers to technology that enhances the real world with digital overlays, allowing users to interact with both physical and digital elements simultaneously.

Wrong options:

• virtual reality: 'Virtual reality' creates a completely immersive digital environment, which is different from the concept of enhancing the real world with additional information.
• artificial intelligence: 'Artificial intelligence' refers to computer systems that simulate human intelligence, which, while relevant, does not specifically address the integration of digital elements into the physical world.
• machine learning: 'Machine learning' is a subset of artificial intelligence focused on data analysis and pattern recognition, which does not directly relate to the concept of augmented reality.