Introduction:
To determine the number of 1-degree carbon atoms in a hydrocarbon, we need to analyze the carbon atoms' degrees in the molecule. The degree of a carbon atom refers to the number of carbon atoms bonded to it. The degrees can be classified as 1, 2, 3, or 4.

Given Information:
- Two 3-degree carbon atoms
- One 2-degree carbon atom

Explanation:

Step 1: Identify the carbon atoms:
In this case, we have a hydrocarbon with three carbon atoms. Let's label them as carbon atoms A, B, and C.

Step 2: Determine the degrees of the carbon atoms:
- Carbon atom A has a degree of 3.
- Carbon atom B has a degree of 3.
- Carbon atom C has a degree of 2.

Step 3: Identify the carbon atoms with 1-degree:
- A 1-degree carbon atom is bonded to three other carbon atoms.
- In this case, carbon atoms A and B have three bonds each, making them 3-degree carbon atoms.
- Carbon atom C has two bonds, making it a 2-degree carbon atom.

Step 4: Calculate the number of 1-degree carbon atoms:
- Since both carbon atoms A and B are 3-degree carbon atoms, they cannot be counted as 1-degree carbon atoms.
- The only carbon atom that meets the condition is carbon atom C, which is a 2-degree carbon atom.
- Therefore, there is only one 1-degree carbon atom in the hydrocarbon.

Summary:
In a hydrocarbon with two 3-degree carbon atoms and one 2-degree carbon atom, there is only one 1-degree carbon atom. The 3-degree carbon atoms (A and B) are bonded to three other carbon atoms, making them unsuitable for being counted as 1-degree carbon atoms. Only the 2-degree carbon atom (C) meets the criteria for being a 1-degree carbon atom.