I piselli surgelati costano meno delle verdure fresche.

Yes. I is the masculine plural definite article, so here it means the.

It is used because piselli is:

• masculine
• plural

The singular is il pisello = the pea
The plural is i piselli = the peas

In Italian, the article often appears even when English might speak more generally. So I piselli surgelati can mean either:

• the frozen peas
• or frozen peas in a general sense, depending on context

Because the sentence is talking about peas in the plural.

• pisello = pea
• piselli = peas

Since the subject is plural, the rest of the sentence also matches that plural idea:

• i piselli
• surgelati
• costano

Surgelati means frozen or more specifically deep-frozen.

So:

• piselli surgelati = frozen peas

It is an adjective, and it agrees with piselli:

• piselli = masculine plural
• surgelati = masculine plural

Related forms:

• surgelato = masculine singular
• surgelata = feminine singular
• surgelate = feminine plural

In Italian, adjectives often come after the noun.

So:

• piselli surgelati = frozen peas
• verdure fresche = fresh vegetables

This is the most normal order here.
If you put the adjective before the noun, it can sometimes sound more literary, emphatic, or slightly different in tone.

Because the subject is plural: i piselli surgelati.

The verb is costare = to cost

Present tense:

• costa = it costs
• costano = they cost

Since peas is plural, Italian uses the plural verb:

• I piselli surgelati costano... = Frozen peas cost...

Meno means less or less than in comparisons.

Here the structure is:

• meno di
  • noun = less than
    • noun

But di combines with the article le:

• di + le = delle

So:

• meno delle verdure fresche = less than the fresh vegetables

This is a very common contraction in Italian.

Because verdure fresche here has a definite article: le verdure fresche.

When di comes before le, they combine:

• di + le = delle

So:

• meno delle verdure fresche

In standard Italian, using the article here sounds natural because the comparison is between two categories:

• i piselli surgelati
• le verdure fresche

Without the article, the sentence would sound different and usually less natural in this context.

Because verdura is a feminine noun.

• la verdura = vegetables / greenery / vegetable produce
• le verdure = vegetables

So in the sentence:

• verdure is plural
• and the adjective must agree with it

That is why we get:

• verdure fresche

not

• verdure freschi

Because fresche describes verdure, and verdure is feminine plural.

Agreement in Italian:

• masculine singular: fresco
• masculine plural: freschi
• feminine singular: fresca
• feminine plural: fresche

So:

• verdure fresche = fresh vegetables

Not normally in this sentence.

The most natural order is:

• piselli surgelati
• verdure fresche

Italian usually places descriptive adjectives like surgelati and fresche after the noun.

Putting them before the noun is sometimes possible in Italian, but it often changes the tone, emphasis, or naturalness. For everyday neutral speech, stick with:

• piselli surgelati
• verdure fresche

Good question. Italian uses both di and che in comparisons, but in different situations.

Use di when comparing:

• nouns
• pronouns
• quantities
• expressions with articles

Here we are comparing one noun phrase with another:

• i piselli surgelati
• le verdure fresche

So di is the correct choice:

• costano meno delle verdure fresche

Very roughly:

• meno di
  • noun
• meno che is used in other comparison patterns

It can mean either, depending on context.

Italian often uses the definite article where English uses a general noun without one.

So this sentence could mean:

• Frozen peas cost less than fresh vegetables
  or
• The frozen peas cost less than the fresh vegetables

Without more context, the sentence can be understood generically.

The structure is:

Subject + verb + comparison

More exactly:

• I piselli surgelati = subject
• costano = verb
• meno delle verdure fresche = comparative phrase

So literally:

• The frozen peas cost less than the fresh vegetables

This is a very normal and straightforward Italian sentence pattern.