Which two characteristics make electromagnetic waves effective in communication? A. They carry information very quickly. B. They move faster through matter than through space. C. They do not require a medium to carry information. D. They carry more energy than visible light.

## Step 1: Identify the Problem<br />### The problem is asking us to identify the two characteristics of electromagnetic waves that make them effective in communication.<br /><br />## Step 2: Evaluate Option A<br />### Option A states that electromagnetic waves carry information very quickly. This is indeed a characteristic of electromagnetic waves, as they can travel at the speed of light, which is approximately \(3 \times 10^8\) meters per second. This allows for rapid communication over long distances.<br /><br />## Step 3: Evaluate Option B<br />### Option B suggests that electromagnetic waves move faster through matter than through space. This is not correct. In fact, electromagnetic waves, including light, actually slow down when they pass through a medium other than a vacuum.<br /><br />## Step 4: Evaluate Option C<br />### Option C states that electromagnetic waves do not require a medium to carry information. This is also true. Electromagnetic waves, including radio waves, microwaves, and light, can travel through the vacuum of space, which is why we can receive signals from satellites and distant stars.<br /><br />## Step 5: Evaluate Option D<br />### Option D suggests that electromagnetic waves carry more energy than visible light. This is not necessarily true. The energy of electromagnetic waves is determined by their frequency, and visible light is just a small part of the electromagnetic spectrum. Some electromagnetic waves, like gamma rays and X-rays, carry more energy than visible light, while others, like infrared and radio waves, carry less.