1. Camphor-Terpene
Camphor is a type of terpene. Terpenes are a large class of organic compounds that are commonly found in plants. They are responsible for the characteristic scents and flavors of many plants and are often used in essential oils and perfumes. Camphor is a specific type of terpene that is derived from the wood of the camphor tree or synthesized from pinene, another terpene.

2. Insulin-Protein
Insulin is a type of protein. Proteins are large, complex molecules that are made up of amino acids. They play many important roles in the body, including acting as enzymes, hormones, and structural components. Insulin is a hormone that is produced by the pancreas and is involved in regulating blood sugar levels. It is made up of two polypeptide chains, A and B, that are connected by disulfide bonds.

3. Nicotine-Alkaloid
Nicotine is a type of alkaloid. Alkaloids are a class of naturally occurring organic compounds that contain nitrogen atoms and have a ring structure. They are often found in plants and have a variety of biological activities. Nicotine is the main psychoactive component of tobacco and is responsible for its addictive properties. It acts as a stimulant and is rapidly absorbed into the bloodstream when tobacco is smoked or chewed.

4. Streptomycin-Carbohydrate
Streptomycin is not related to carbohydrates. Streptomycin is an antibiotic that is derived from the bacterium Streptomyces griseus. It is used to treat bacterial infections, particularly tuberculosis. Carbohydrates, on the other hand, are a class of organic compounds that are composed of carbon, hydrogen, and oxygen atoms. They are an important source of energy for living organisms and play many other roles in the body, such as providing structural support and serving as cell surface markers.

In summary, the correct number of relationships among the given pairs is 4. Camphor is a type of terpene, insulin is a type of protein, nicotine is a type of alkaloid, and streptomycin is not related to carbohydrates.