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Following a Chain of Causes is a free printable Grade 4 English worksheet on holding a multi-step causal chain together, aligned to Common Core standard RI.4.10. It prints 2 questions with an answer key on its own sheet of paper, in 25 versions that each ask different questions, so no two pupils in the class work from the same page. Print it from the browser or download it as a PDF — no account, no email.

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Set 1 has all 25 in a single PDF. All 25 sets ask different questions.

Following a Chain of Causes

RI.4.10

NameDate

Read the text, then answer the questions.

1.Read the text, then answer the questions.

The Wolves and the Rivers

Wolves were shot out of Yellowstone by 1926. Fourteen were brought back in 1995. With no wolves, elk had grazed the valleys freely for seventy years. Young willow and aspen were eaten as soon as they grew. The wolves killed some elk. More importantly, they changed where elk would stand still. Open valley floors became dangerous, so the elk stopped lingering there. Willow and aspen grew back along the rivers. Beavers, which need willow, returned. Their dams made ponds. Roots held the banks. The rivers narrowed, deepened and moved less. Some researchers describe this as wolves changing the shape of rivers, though others argue the effect has been overstated.

  1. 1. Explain the relationship between the wolves and the shape of the rivers.
  2. 2. Put these in order: beavers return, wolves are reintroduced, willow grows back.
  3. 3. Summarise this text.
2.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. 1. Put these in order: the coral turns white, the water warms, the polyps expel the algae.
  2. 2. Summarise this text.
  3. 3. Explain the relationship between the polyp and the algae.

LessonPrint · RI.4.10 · Set 2 · free to copy for classroom use

Answer key — Following a Chain of Causes

Set 2. Prints on its own sheet.

  1. 1.1. Wolves made valley floors dangerous, so elk moved on, willow grew, beavers returned and dammed, and roots held the banks. 2. Wolves are reintroduced, willow grows back, beavers return. 3. Wolves returned to Yellowstone in 1995, changed where elk grazed, allowed willow and beavers back, and are credited — with some dispute — with reshaping the rivers.
  2. 2.1. The water warms, the polyps expel the algae, the coral turns white. 2. Coral reefs are built by pinhead-sized polyps that make calcium cups and live in partnership with algae, and warm water breaks that partnership and bleaches the reef. 3. The algae make food from sunlight and give most of it to the polyp; the polyp gives them shelter and its waste. Neither builds a reef alone.

Last reviewed 2026-09-05. Aligned to RI.4.10 of the Common Core State Standards for English language arts.