Update README.md

1-getting-started/lessons/1-introduction-to-iot/README.md

@@ -28,7 +28,7 @@ The term 'Internet of Things' was coined by [Kevin Ashton](https://wikipedia.org
 >
 > **Actuators** convert electrical signals into real-world interactions such as levers, turning on lights, making sounds, or sending control signals to other hardware such as to turn on a power socket
 
-IoT as a technology area is more than just devices - it includes cloud based services that can process the sensor data, or send requests to actuators connected to IoT devices. It also includes devices that don't have connectivity, often referred to as [edge devices](https://en.wikipedia.org/wiki/Edge_device), that can process and respond to sensor data themselves, usually using AI models trained in the cloud.
+IoT as a technology area is more than just devices - it includes cloud based services that can process the sensor data, or send requests to actuators connected to IoT devices. It also includes devices that don't have connectivity, often referred to as edge devices, that can process and respond to sensor data themselves, usually using AI models trained in the cloud.
 
 IoT is a fast growing technology field. It is estimated that by the end of 2020, 30 billion IoT devices were deployed and connected to the Internet. Looking to the future, it is estimated that by 2025, IoT devices will be gathering almost 80 zettabytes of data, or 80 trillion gigabytes. That's a lot of data!
 
@@ -36,13 +36,13 @@ IoT is a fast growing technology field. It is estimated that by the end of 2020,
 
 ✅ Do a little research: how much of the data generated by IoT devices is actually used, and how much is wasted? Why is so much data ignored?
 
-This data is the key to IoT's success. To be a successful IoT developer, you need to understand the data you need to gather, how to gather it, how to make decisions based on it, and how to use those decisions to interact back with the physical world if needed.
+This data is the key to IoT's success. To be a successful IoT developer, you need to understand the data you need to gather, how to gather it, how to make decisions based off it, and how to use those decisions to interact back with the physical world if needed.
 
 ## IoT devices
 
 The **T** in IoT stands for **Things** - devices that interact with the physical world around them either by gathering data from sensors, or providing real-world interactions via actuators.
 
-Devices for production or commercial use, such as the consumer fitness trackers, or industrial machine controllers, are usually custom made. They use custom circuit boards, maybe even custom processors, designed to meet the needs of a particular task, whether that's being small enough to fit on a wrist, or rugged enough to work at a high temperature, high stress, high vibration factory environment.
+Devices for production or commercial use, such as the consumer fitness trackers, or industrial machine controllers, are usually custom made. They use custom circuit boards, maybe even custom processors, designed to meet the needs of a particular task, whether that's being small enough to fit on a wrist, or rugged enough to work in a high temperature, high stress, high vibration factory environment.
 
 As a developer, either learning about IoT or creating a prototype device, you'll need to start with a developer kit. These are general purpose IoT devices designed for developers to use, often with features that you wouldn't see on a production device, such as a set of external pins to connect sensors or actuators to, hardware to support debugging, or additional resources that would add unnecessary cost when doing a large manufacturing run.
 
@@ -80,7 +80,7 @@ A single-board computer is a small computing device that has all the elements of
 
 ***Raspberry Pi 4. Michael Henzler / [Wikimedia Commons](https://commons.wikimedia.org/wiki/Main_Page) / [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0/)***
 
-The Raspberry Pi is one of the most popular single-board computer.
+The Raspberry Pi is one of the most popular single-board computers.
 
 Like a microcontroller, single-board computers have a CPU, memory and input/output pins, but they have additional features such as a graphics chip to allow you to connect monitors, audio outputs, and USB ports to connect keyboards mice and other standard USB devices like webcams or external storage. Programs are stored on SD cards or hard drives along with an operating system, instead of a memory chip built into the board.
 
@@ -176,7 +176,7 @@ Infrastructure IoT is monitoring and controlling the local and global infrastruc
 
 [Smart Cities](https://wikipedia.org/wiki/Smart_city) are urban areas that use IoT devices to gather data about the city and use that to improve how the city runs. These cities are usually run with collaborations between local governments, academia and local businesses, tracking and managing things varying from transport to parking and pollution. For example, in Copenhagen, Denmark, air pollution is important to the local residents, so it is measured and the data is used to provide information on the cleanest cycling and jogging routes.
 
-[Smart power grids](https://wikipedia.org/wiki/Smart_grid) allow better analytics of power demand by gathering usage data at the level of individual homes. This data can guide decisions at a country level including where to build new power stations, and at a personal level by giving user insights into how much power they are using, when they are using it, and even suggestions on how to reduce costs, such as charging electric cars at night.
+[Smart power grids](https://wikipedia.org/wiki/Smart_grid) allow better analytics of power demand by gathering usage data at the level of individual homes. This data can guide decisions at a country level including where to build new power stations, and at a personal level by giving users insights into how much power they are using, when they are using it, and even suggestions on how to reduce costs, such as charging electric cars at night.
 
 ✅ If you could add IoT devices to measure anything where you live, what would it be?