How many of the given statements are incorrect?
A. The sternum is the part of appendicular skeleton.
B. 7 ribs are true ribs.
C. The longest bone in our body is the femur.

Options

A. None
B. One
C. Two
D. All

Answer

To determine how many of the given statements are incorrect, we will analyze each statement one by one.

### Step 1: Analyze the first statement
**Statement A:** "The sternum is the part of appendicular skeleton."

- The sternum, also known as the breastbone, is actually part of the axial skeleton, not the appendicular skeleton. The axial skeleton comprises the skull, vertebral column, and rib cage, including the sternum. Therefore, this statement is **incorrect**.

### Step 2: Analyze the second statement
**Statement B:** "7 ribs are true ribs."

- True ribs are defined as the first seven pairs of ribs that are directly attached to the sternum via costal cartilage. This statement is **correct**.

### Step 3: Analyze the third statement
**Statement C:** "The longest bone in our body is the femur."

- The femur, also known as the thigh bone, is indeed the longest bone in the human body. This statement is also **correct**.

### Conclusion
Now, we need to count how many statements are incorrect:
- Statement A: Incorrect
- Statement B: Correct
- Statement C: Correct

Thus, there is **only one incorrect statement**.

### Final Answer
The number of incorrect statements is **1**.

---