Question

in 1986, the worlds worst nuclear power plant accident occurred at chernobyl, ukraine, in the former soviet union. a chemical explosion and fire released more than fifty tons of radiation into the atmosphere. an emergency team responded by pouring boron and sand on the debris. the boron was meant to prevent more nuclear reactions; the sand was to stop the fire and release of radiation. soon after the accident, a team built a concrete and steel structure, known as a sarcophagus, to prevent rainwater from causing another explosion. over time, however, a new complication arose: the structure eroded. this crisis inspired more than forty countries and organizations to find a better answer. an enormous structure called the new safe confinement (nsc) was built. the nsc covers the sarcophagus and forms an airtight seal. match the problems with their solutions. a crew built a concrete structure to seal the reactor. a crew poured sand on the reactor. the nsc was built.

Explanation:

To solve the problem of matching problems with solutions, we analyze the text:

1. Problem 1: Chemical explosion and fire releasing radiation

Solution: "A crew poured sand on the reactor" (sand stops fire/radiation release).

1. Problem 2: Prevent rainwater from causing another explosion

Solution: "A crew built a concrete structure to seal the reactor" (concrete sarcophagus prevents rainwater issues).

1. Problem 3: Eroded sarcophagus (new complication)

Solution: "The NSC was built" (NSC covers sarcophagus with airtight seal).

Answer:

• Problem (Chemical explosion/fire): Solution - A crew poured sand on the reactor.
• Problem (Rainwater explosion risk): Solution - A crew built a concrete structure to seal the reactor.
• Problem (Eroded sarcophagus): Solution - The NSC was built.