What type of effect does Coffee have on humans?

Context: "Coffee is a beverage prepared from roasted coffee beans. Darkly colored, bitter, and slightly acidic, coffee has a stimulating effect on humans, primarily due to its caffeine content. It has the highest sales in the world market for hot drinks.

Seeds of the Coffee plant's fruits are separated to produce un-roasted green coffee beans. The beans are roasted and then ground into fine particles that are typically steeped in hot water before being filtered out, producing a cup of coffee. It is usually served hot, although chilled or iced coffee is common. Coffee can be prepared and presented in a variety of ways. Sugar, sugar substitutes, milk, and cream are often used to mask the bitter taste or enhance the flavor."

Answer: Coffee has a stimulating effect on humans, primarily due to its caffeine content.