Explica brevemente el proceso por el cual las hojas secas que mezclamos con el suelo frente al huerto, acabarán siendo nutrientes disponibles para las plantas

C. Answer the questions. 1. What part of your skeleton can bend without breaking? 2. What do blood vessels do in the bones? 3. Where do new red blood cells come from? 4. What is an unborn baby's skeleton made of? 5. What shapes and supports your arms and legs?

A. Write the letter for the correct answer. \( \begin{array}{lll}\text { 1. The muscular system has } & \\ \begin{array}{lll}\text { (a) two } & \text { (b) three } & \text { (c) ten }\end{array} \\ \text { 2. Muscles are made of muscles. } \\ \begin{array}{lll}\text { (a) cells } & \text { (b) tendons } & \text { (c) ligaments }\end{array}\end{array} \).

Use each word to write a sentence about how your body moves. 1. hinge joint 2. ball-and-socket joint

Answer True or False. 1. Cartilage is harder than bone. 2. You have the same amount of cartilage in your body all your life. 3. Bones can repair themselves. 4. Red blood cells are made in marrow. 5. Bones always stay the same size. 6. Some cartilage changes to bone.

A. Answer True or False. 1. The skull is shaped like a cage. 2. The backbone is made up of many vertebrae.