Ava had a pet goldfish, and she loved feeding it and watching it swim around in its bowl. After four months, she noticed that her fish hadn't grown much, so she looked up information about caring for goldfish. She learned that unless she made changes, her goldfish would remain small. Look at the picture, and choose the correct words to finish the sentences.

The image shows an example of a(n) _ affecting her fish's growth. Other conditions that could affect animal growth include _.

Word Bank: life cycle | internal environmental factor | genes | hormones | external environmental factor | metamorphosis​