why put "ed"

[endeavor6636]

The Nasturtiums receive their name from the fact that they produce an oil that is similar to that produced by Watercress (Nasturtium officinale), from the family Brassicaceae.


why we have to put "ed" at the end of the underlined word produced ? instead of just "produce"

[bkk_kid]

(is) produced --> it can't produce itself, right?

[Coffa]

Originally Posted by endeavor6636

The Nasturtiums receive their name from the fact that they produce an oil that is similar to that produced by Watercress (Nasturtium officinale), from the family Brassicaceae.


why we have to put "ed" at the end of the underlined word produced ? instead of just "produce"

If we expand the clause that contains "produced", we get:

"...that is similar to (the oil that is) produced by Watercress..."

In other words, the oil is produced by Watercress. This is the present tense passive mood, which is formed in English by the present tense of the verb 'to be' and the past participle. The past participle of 'to produce' is 'produced', and this is why it is used here, rather then 'produce'.

[endeavor6636]

oh isee, yes i got it now, thanks all