constructed
"Fungus" is a noun, not a verb. Nouns do not have past participles, or any other participles.
The past tense for construct is constructed.
BUY
First of all know what is participles . The third form of the verb is called a participles. So in the mode of tenses it will be changed . With present tense it is present participle and with future tense it will be future participle.
The word "liberty" is a noun and so doesn't have a past tense.
"Mixture" is a noun. Only verbs have tenses, past participles, and present participles. "Mix" is a verb. The past tense and past participle of "mix" is "mixed".
The past tenses are drew and broke. The past participles are drawn and broken.
Ear is a noun, and nouns cannot be changed into past tense or past participles.
The past tense of "sting" is "stung" and the past participle is also "stung."
The simple past and past participle are both "looked".
Observed is the past tense and past participle of the verb observe. Past participles can be used as adjectives. Example: observed behavior.
Standing is not past tense. It is the present participle of the verb "stand". Present participles require the use of auxiliary verbs to show tense. Examples: was/were standing (past progressive) am/is/are standing (present progressive) will be standing (future progressive) Stood is the past tense of stand.