If an initial population of bacteria doubles every hour, what is the growth factor of this exponential model?

B. Write the letter for the correct answer. \( \begin{array}{lll}\text { 1. A vertebra is part of the } \\ \begin{array}{lll}\text { (a) skull } & \text { (b) backbone } & \text { (c) rib cage }\end{array} \\ \begin{array}{lll}\text { 2. The ribs are attached to the }\end{array} \\ \begin{array}{lll}\text { (a) skull } & \text { (b) brain } & \text { (c) backbone }\end{array} \\ \begin{array}{lll}\text { 3. A group of bones that protects the brain is the } \\ \text { (a) skull } & \text { (b) backbone } & \text { (c) rib cage }\end{array} \\ \begin{array}{lll}\text { 4. The backbone is made up of many cords } & \text { (b) ribs } & \text { (c) vertebrae }\end{array}\end{array} \).

D. Answer the questions. 1. What tissues hold bones together? 2. How do hinge joints work? 3. What kind of joint can move in a complete circle?

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

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

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?