Differentiate between acids and bases on the basis of their pH values. Give an example of each type.

Bases are the chemical opposite of acids. Acids are defined as compounds that donate a hydrogen ion (H+) to another compound.

Definition of Acids - An acid is any chemical compound which when dissolved in water gives a solution with a hydrogen ion activity greater than in pure water. Bronstead Lowry

Definition of Base - A base is an aqueous substance that can accept hydrogen ions. Bronstead Lowry Definition: A base is any substance which accepts a proton.

Physical Characteristics of Acids - Depending on the temperature, acids can occur in solid, liquid or gaseous form. Taste sour.

Physical Characteristics of Base - Bases feel slippery because of the reaction of the base with the oils of your hand. Frequently solids except ammonia which is a gas. Taste bitter.

Properties of Acids - Electrolytes, conduct electricity (because electrolytes), react with many metals.

Properties of Base - Electrolytes, conduct electricity, ranges from insoluble to so soluble that they can react with water vapor.

Acids are often used to remove rust from metals, as an electrolyte in batteries, for mineral processing, to produce fertilizers and gasoline and as additives in food and beverages. Bases are used primarily in cleaning as dishwashing and laundry detergents, oven cleaners and stain removers.

Here are some differences! Hope this helps, sorry I couldn't think of anything else. ;(

the answer is b because, investigating whether another species of moth also drinks tears might be interesting, but it would not directly explain why this species of moth does.

to explain why this species of moth drinks tears, the scientist could ask: "what nutrients that moths need are in elephant tears? "

the scientist could experiment with moth repellent or oter ways to keep the moths away, but that would not answer his original question.