A Speaker's Reasons and Evidence
SL.4.3
Read the text, then answer the questions.
What a Coral Reef Is
A coral reef looks like rock and is built by animals. A coral polyp is a soft creature the size of a pinhead. It draws calcium from the sea water and builds a hard cup around itself. Millions of polyps, cup upon cup, become a reef. Inside each polyp live tiny algae. The algae make food from sunlight and pass most of it to the polyp. In exchange they get shelter and the polyp's waste. Neither could build a reef alone. When the water gets too warm, the polyps expel the algae. Without them the coral turns white and starves. That is what bleaching means. A reef takes centuries to build and can bleach in a single hot summer.
- 1. What is the author's purpose, and how do you know?
- 2. Quote the words that explain what the algae give the polyp.
- 3. The text says neither organism could build a reef alone. What evidence supports that?
What a Beaver Dam Does
A beaver does not build a dam for shelter. It builds one to make a pond, and it lives in a lodge in the pond. The dam raises the water so the lodge entrance stays underwater. A predator that cannot swim cannot get in. But the pond does far more than protect one family. Behind a dam, water slows, and slow water drops the silt it carries. Over years this builds rich wet ground. That ground holds water in a drought and holds it back in a flood. It supports plants, insects, amphibians and birds that were not there before. Where beavers have been reintroduced, the number of species in a valley typically rises within five years.
- 1. Quote the words that explain what slow water does.
- 2. What is the author's purpose, and how do you know?
- 3. The text says the pond does more than protect one family. What evidence supports that?
LessonPrint · SL.4.3 · Set 12 · free to copy for classroom use