The verbal system lacks a distinctive future tense (the present tense serves here) and features special forms to express an action performed by an undetermined subject (the "impersonal").
What does Estonian use to show actions performed by an undecided subject?
special forms

Many cultures define the transition into adultlike sexuality by specific biological or social milestones in an adolescent's life. For example, menarche (the first menstrual period of a female), or semenarche (the first ejaculation of a male) are frequent sexual defining points for many cultures. In addition to biological factors, an adolescent's sexual socialization is highly dependent upon whether their culture takes a restrictive or permissive attitude toward teen or premarital sexual activity. Restrictive cultures overtly discourage sexual activity in unmarried adolescents or until an adolescent undergoes a formal rite of passage. These cultures may attempt to restrict sexual activity by separating males and females throughout their development, or through public shaming and physical punishment when sexual activity does occur. In less restrictive cultures, there is more tolerance for displays of adolescent sexuality, or of the interaction between males and females in public and private spaces. Less restrictive cultures may tolerate some aspects of adolescent sexuality, while objecting to other aspects. For instance, some cultures find teenage sexual activity acceptable but teenage pregnancy highly undesirable. Other cultures do not object to teenage sexual activity or teenage pregnancy, as long as they occur after marriage. In permissive societies, overt sexual behavior among unmarried teens is perceived as acceptable, and is sometimes even encouraged. Regardless of whether a culture is restrictive or permissive, there are likely to be discrepancies in how females versus males are expected to express their sexuality. Cultures vary in how overt this double standard is—in some it is legally inscribed, while in others it is communicated through social convention. Lesbian, gay, bi-sexual and transsexual youth face much discrimination through bullying from those unlike them and may find telling others that they are gay to be a traumatic experience. The range of sexual attitudes that a culture embraces could thus be seen to affect the beliefs, lifestyles, and societal perceptions of its adolescents.
What word refers to the first menstrual period in females?
menarche

Iranian scientists outside Iran have also made some major contributions to science. In 1960, Ali Javan co-invented the first gas laser, and fuzzy set theory was introduced by Lotfi Zadeh. Iranian cardiologist, Tofy Mussivand invented and developed the first artificial cardiac pump, the precursor of the artificial heart. Furthering research and treatment of diabetes, HbA1c was discovered by Samuel Rahbar. Iranian physics is especially strong in string theory, with many papers being published in Iran. Iranian-American string theorist Kamran Vafa proposed the Vafa-Witten theorem together with Edward Witten. In August 2014, Maryam Mirzakhani became the first-ever woman, as well as the first-ever Iranian, to receive the Fields Medal, the highest prize in mathematics.
Which Iranian scientist co-invented the first gas laser?
Ali Javan