*Question*
Answer the following question given this paragraph: The Arrhenius definition of acids and bases is somewhat limited. There are some compounds whose properties suggest that they are either acidic or basic, but which do not qualify according to the Arrhenius definition. An example is ammonia (NH 3 ). Its aqueous solution turns litmus blue, it reacts with acids, and displays all the other properties of a base. However, it does not contain the hydroxide ion. In 1923, a broader definition of acids and bases was independently proposed by Danish chemist Johannes Brnsted (1879-1947) and English chemist Thomas Lowry (1874-1936). A Brnsted-Lowry acid is a molecule or ion that donates a hydrogen ion in a reaction. A Brnsted-Lowry base is a molecule or ion that accepts a hydrogen ion in a reaction. A hydrogen ion is commonly referred to as a proton, and so acids and bases are proton donors and proton acceptors respectively according to the Brnsted-Lowry definition. All substances that are categorized as acids and bases under the Arrhenius definition are also defined as such under the Brnsted-Lowry definition. The new definition, however, includes some substances that are left out according to the Arrhenius definition. Q: Which type of substance is considered a proton donor in a reaction? Choices: - base - carbon - oxygen - acid A:
**Answer**
acid

*Question*
Answer the following question given this paragraph: Carbon dioxide is the main greenhouse gas causing global warming. There are several possible ways to reduce carbon dioxide emissions. They include cap-and-trade systems, carbon taxes, and carbon sequestration. Q: What is the main greenhouse gas causing global warming? Choices: - nitrogen - sulfur - carbon monoxide - carbon dioxide A:
**Answer**
carbon dioxide

*Question*
Answer the following question given this paragraph: Physical science is the study of matter and energy. That covers a lot of territory because matter refers to all the "stuff" that exists in the universe. It includes everything you can see and many things that you cannot see, including the air around you. Energy is also universal. It's what gives matter the ability to move and change. Electricity, heat, and light are some of the forms that energy can take. Q: What branch of science is the study of matter and energy? Choices: - unnatural science - natural science - negative science - physical science A:
**Answer**
physical science

*Question*
Answer the following question given this paragraph: Innate behaviors do not have to be learned or practiced. Q: What type of behaviors do not have to be learned or practiced? Choices: - protective behaviors - acquired behaviors - diverse behaviors - innate behaviors A:
**Answer**
innate behaviors