Educational worksheet on the skeletal system for fifth-grade students, including questions, definitions, and a labeled skeleton diagram.

Let's solve each part of this Skeletal System worksheet step by step and provide clear explanations.

---

1. Fill in the blanks

a. The skeletal system is made up of _______.
✔ Answer: *Bones*
Explanation: The skeletal system consists of bones that support the body, protect internal organs, and allow movement.

---

b. Rib cage protects our ______ and ______.
✔ Answer: *Heart* and *Lungs*
Explanation: The rib cage (made of ribs and sternum) surrounds and protects vital organs in the chest cavity — primarily the heart and lungs.

---

c. The muscle where two or more ______ meet is called a joint.
✔ Answer: *Bones*
Explanation: A joint is the place where two or more bones connect. For example, the knee joint connects the femur and tibia.

---

d. Muscle of the stomach are an example of ______ muscles.
✔ Answer: *Smooth*
Explanation: The stomach has smooth muscles, which are involuntary muscles found in internal organs like the digestive tract. They contract automatically to help move food.

---

2. Tick (√) the correct word

a. The skull have (22 / 28) different bones.
✔ Answer: *22*
Explanation: The human skull is made up of 22 bones, including 8 cranial bones and 14 facial bones.

> Note: "Have" should be "has" grammatically, but since it's a multiple-choice format, we focus on content.

---

b. Femur is the (longest / smallest) bone in our body.
✔ Answer: *Longest*
Explanation: The femur (thigh bone) is the longest bone in the human body.

---

c. (Enamel / girdle) is the hardest substance in our body.
✔ Answer: *Enamel*
Explanation: Tooth enamel is the hardest and most mineralized substance in the human body. The "girdle" refers to the shoulder or pelvic girdle, not a material.

---

d. Lower leg has two bones called fibula and (tibula / tibia).
✔ Answer: *Tibia*
Explanation: The lower leg contains two bones: the tibia (larger, weight-bearing bone) and the fibula (smaller, thinner bone).

---

3. Define

a. Bone marrow
✔ Definition: Bone marrow is a soft, spongy tissue found inside certain bones (like hip and spine). It produces blood cells — red blood cells, white blood cells, and platelets.

---

b. Ligaments
✔ Definition: Ligaments are tough, flexible bands of connective tissue that connect bone to bone at joints. They stabilize and support joints.

---

c. Tendons
✔ Definition: Tendons are strong, fibrous tissues that connect muscles to bones. They transmit the force from muscles to bones, enabling movement.

---

4. Label the human skeletal system

*(Note: Since no image is provided here, I will describe how to label based on common diagrams.)*

Typically, such diagrams show:

- Top arrow pointing to the head: Label as Skull
- Middle arrow pointing to the upper chest area: Label as Rib cage or Thoracic cage
- Lower arrow pointing to the lower back/hip area: Label as Pelvis or Hip bone

Alternatively, if arrows point to specific parts:
- Skull → Skull
- Ribs → Rib cage
- Pelvis → Pelvic bone

✔ Labels:
1. Skull
2. Rib cage
3. Pelvis

> If there are other parts shown (like spine, femur, etc.), they may also be labeled accordingly.

---

✔ Final Answers Summary:

#### 1. Fill in the blanks
a. Bones
b. Heart, Lungs
c. Bones
d. Smooth

#### 2. Tick the correct word
a. 22
b. Longest
c. Enamel
d. Tibia

#### 3. Definitions
a. Bone marrow – Soft tissue inside bones that produces blood cells.
b. Ligaments – Connect bone to bone; stabilize joints.
c. Tendons – Connect muscle to bone; enable movement.

#### 4. Labeling
- Top: Skull
- Middle: Rib cage
- Bottom: Pelvis

---

Let me know if you'd like a printable version or a diagram sketch description!