Meaning: 'Electric' refers to something that operates using electricity, such as electric can openers.

Wrong options:

• electrical: While 'electrical' is also an adjective, it generally refers to the field of electricity rather than describing devices directly, making it less suitable here.
• electronic: 'Electronic' pertains to devices that use electronic circuits, which is not the intended meaning for can openers, thus it doesn't fit.
• electricity: 'Electricity' is a noun and cannot modify 'can openers' as it does not function as an adjective.

Correct answer: demanding

Explanation: The word 'demanding' is an adjective that describes something requiring a lot of effort, fitting well in the context of physical activity and aligning with the grammatical structure of the sentence.

Meaning: 'Demanding' means requiring a lot of physical effort or energy, which is appropriate in the context of exercise.

Wrong options:

• need: 'Need' is a verb and does not fit grammatically in this context where an adjective is required.
• pushing: 'Pushing' is a gerund or present participle that does not convey the intended meaning of requiring effort in this context.
• supplying: 'Supplying' is a verb that does not relate to the physical effort required, making it unsuitable.

Correct answer: much

Explanation: The word 'much' is used with uncountable nouns like 'fat,' making it grammatically correct in this context, where we refer to an amount of fat carried by the body.

Meaning: 'Much' refers to a large quantity of something uncountable, in this case, fat.

Wrong options:

• many: 'Many' is used with countable nouns, which does not apply here since 'fat' is uncountable.
• few: 'Few' implies a small number and is used with countable nouns, making it incorrect in this context.
• several: 'Several' also refers to countable nouns and does not fit with the uncountable noun 'fat'.

Correct answer: main

Explanation: The word 'main' is an adjective that indicates the primary or most important ways, fitting grammatically and contextually in the sentence.

Meaning: 'Main' means the most important or primary, which is appropriate when discussing ways to increase calorie expenditure.

Wrong options:

• large: 'Large' describes size rather than importance, making it unsuitable in this context.
• odd: 'Odd' implies something unusual or strange, which does not relate to the concept of primary ways, thus it is incorrect.
• substantial: 'Substantial' means considerable in amount or importance, but it does not convey the idea of being primary as effectively as 'main'.

Correct answer: daily

Explanation: The word 'daily' is an adjective that describes something occurring every day, fitting well in the context of a routine, which is typically a daily occurrence.

Meaning: 'Daily' means occurring every day, which is relevant when discussing routines.

Wrong options:

• usual: 'Usual' refers to something that is common or habitual but does not specifically imply frequency like 'daily' does.
• common: 'Common' indicates something that is frequent or widespread but lacks the specificity of daily occurrence.
• simple: 'Simple' refers to something easy or uncomplicated, which does not relate to the frequency of a routine.