Meaning: "calcium" means a mineral important for bones.

Wrong options:

• calcuim: Two letters are in the wrong order. Check the letters: "calcium". A small spelling mistake loses the mark.
• calsium: It has "s" where the word has "c". Write "calcium". Only the exact spelling gets the mark.

Correct answer: electricity

Explanation: On the recording you hear "a jolt of electricity to". You hear "a jolt of", so you need a word for power.

Meaning: "electricity" means the power that flows as electric charge.

Wrong options:

• electicity: It leaves out the "r". Write "electricity". Only the exact spelling gets the mark.

Correct answer: investigators

Explanation: Listen again to "The investigators placed sweet potatoes". It comes after "The", so you need a word for people, more than one.

Meaning: "investigators" means the people who did the research.

Wrong options:

• investegators: It has "e" where the word has "i". Write "investigators". Only the exact spelling gets the mark.
• investigator: "investigator" has no "s" at the end. The speaker says "investigators", so write the "s".

Correct answer: stressed

Explanation: Here you hear "the electric zap stressed the potatoes". The sentence reports what happened, so the word ends in ed.

Meaning: "stressed" means caused strain or pressure that made the plant react.

Wrong options:

• strested: It has "t" where the word has "s". Check the letters: "stressed". A small spelling mistake loses the mark.
• stress: "stress" is missing the ending. The speaker says "stressed", with "ed" at the end.

Correct answer: mechanism

Explanation: The speaker says "producing more polyphenols as a protective mechanism". After "a" you need a word for a thing.

Meaning: "mechanism" means the natural way the plant protects itself.

Wrong options:

• mechanisim: It adds an extra "i". The right spelling is "mechanism". Every letter must be correct to get the mark.

Correct answer: counted

Explanation: You hear "shock counted therapy to Re-Start". The form is a past action, so ends in ed.

Meaning: "counted" means added up or considered here.

Wrong options:

• countet: It has "t" where the word has "d". Check the letters: "counted". A small spelling mistake loses the mark.
• mounted: This is a different word. The sentence needs the word meaning was counted or considered.