Question: in the play King Lear, Edmund the antagonist is flirting with two sister and one of them has what type of rare trait?

Context paragraphs:
Vocal learning: Vocal learning is the ability to modify acoustic and syntactic sounds, acquire new sounds via imitation, and produce vocalizations.  "Vocalizations" in this case refers only to sounds generated by the vocal organ (mammalian larynx or avian syrinx) as opposed to by the lips, teeth, and tongue, which require substantially less motor control.  A rare trait, vocal learning is a critical substrate for spoken language and has only been detected in eight animal groups despite the wide array of vocalizing species; these include humans, bats, cetaceans, pinnipeds (seals and sea lions), elephants, and three distantly related bird groups including songbirds, parrots, and hummingbirds.  Vocal learning is distinct from auditory learning, or the ability to form memories of sounds heard, a relatively common trait which is present in all vertebrates tested.  For example, dogs can be trained to understand the word "sit" even though the human word is not in its innate auditory repertoire (auditory learning).  However, the dog cannot imitate and produce the word "sit" itself as vocal learners can.

Limnonectes palavanensis: Limnonectes palavanensis (common names: smooth guardian frog, Palawan wart frog) is a species of frog in the Dicroglossidae family.  It is found in the Palawan Island (its type locality), the Philippines, and Borneo (Brunei, Indonesia, Malaysia).  The species shows paternal care, a relatively rare trait in frogs.

Re Lear: Re Lear (] ; Italian for "King Lear") is an Italian operatic libretto in four acts written by Antonio Somma for the Italian opera composer Giuseppe Verdi.  It was based on "King Lear", "the Shakespeare play with which Verdi struggled for so many years, but without success".

Cordelia (King Lear): Cordelia is a fictional character in William Shakespeare's tragic play, "King Lear".  She is the youngest of King Lear's three daughters, and his favourite.  After her elderly father offers her the opportunity to profess her love to him in return for one third of the land in his kingdom, she refuses and is banished for the majority of the play.

King Lear (1910 film): King Lear (Italian: "Re Lear" ) is a 1910 Italian silent historical drama film directed by Gerolamo Lo Savio and starring Ermete Novelli, Francesca Bertini and Olga Giannini Novelli.  It is an adaptation of William Shakespeare's "King Lear".

King Lear (1999 film): King Lear is a 1999 adaptation of William Shakespeare's play of the same name.  The film stars Brian Blessed (who also co-directed the film, along with Tony Rotherham) in the title role.  Apart from Peter Brook's "King Lear" in 1971, it is the only other feature length film adaptation to preserve Shakespeare's verse.  Yvonne Griggs, in "Shakespeare's King Lear: A close study of the relationship between text and film" (2009), characterised it as "a very stilted costume drama".

King Lear (1987 film): King Lear is a 1987 film directed by Jean-Luc Godard, an adaptation of Shakespeare's play in the style of experimental French New Wave cinema.  The script was primarily by Peter Sellars and Tom Luddy, and was originally assigned to Norman Mailer.  It is not a typical cinematic adaptation of Shakespeare's tragedy "King Lear", although some lines from the play are used in the film.  Only three characters – Lear, Cordelia and Edgar – are common to both, and only Act I, scene 1 is given a conventional cinematic treatment in that two or three people actually engage in relatively meaningful dialogue.

The Tragedy of King Lear (screenplay): The Tragedy of King Lear is an unpublished screenplay by Harold Pinter.  It is an adaptation of William Shakespeare's "King Lear" and was commissioned by actor and director Tim Roth with backing from Film Four.  Pinter completed the screenplay on 31 March 2000, but as of 2017 it has not yet been filmed.  It is one of only three screenplays that Pinter adapted from another dramatist's play; the others being his screenplay adaptation of "Butley", by his good friend Simon Gray, and "Sleuth", originally written for the stage by Anthony Shaffer.

Goneril: Goneril is a character in Shakespeare's tragic play "King Lear" (1605).  She is the eldest of King Lear's three daughters.  Along with her sister Regan, Goneril is considered a villain, obsessed with power and overthrowing her elderly father as ruler of the kingdom of Britain.  Her aggressiveness is a rare trait for a female character in Elizabethan literature.

Edmund (King Lear): Edmund or Edmond is a fictional character and the main antagonist in William Shakespeare's "King Lear".  He is the illegitimate son of the Earl of Gloucester, and the younger brother of Edgar, the Earl's legitimate son.  Early on in the play, Edmund resolves to get rid of his brother, then his father, and become Earl in his own right.  He later flirts with both Goneril and Regan and attempts to play them off against each other.

Supporting paragraphs: Edmund (King Lear) Goneril
Answer: aggressiveness