Questions: What is a tectonic plate? * A region deep within Earth A continuous layer of rock that completely covers Earth A large slab of Earth's lithosphere A large slab of Earth's mantle

The answer is the third one: A large slab of Earth's lithosphere.

Explanation for each option:

1. A region deep within Earth: This is incorrect. Tectonic plates are not regions deep within the Earth; they are part of the Earth's outer shell.

2. A continuous layer of rock that completely covers Earth: This is incorrect. Tectonic plates are not a continuous layer; they are separate pieces that fit together like a jigsaw puzzle on the Earth's surface.

3. A large slab of Earth's lithosphere: This is correct. Tectonic plates are large slabs of the lithosphere, which includes the crust and the uppermost part of the mantle. These plates float on the semi-fluid asthenosphere beneath them.

4. A large slab of Earth's mantle: This is incorrect. While tectonic plates include the uppermost part of the mantle, they are not composed entirely of mantle material. They also include the Earth's crust.

In summary, tectonic plates are large slabs of Earth's lithosphere that move and interact at their boundaries, leading to geological phenomena such as earthquakes, volcanic activity, and the creation of mountain ranges.