When an igneous rock forms on top of the Earth's surface it cools quickly and there is almost no time for crystals to form. Obsidian shown below is an example. What type of igneous rock is this?

Which of the following statements is true? 1. the mantle of the earth is made of solid nickel and iron. 2. the crust of the earth is made of solid nickel and iron. 3. the inner core is made of solid nickel and iron.

What are the responsibilities of the region of the brain highlighted below? =+= will rate brainiest =+=

Penelope studies how the structure and function of the nervous system is related to behavior. she is a psychologist