Reproduction

Earthworms, sponges, tapeworms, and leeches possess both male and female reproductive organs in the same individual and are classic hermaphrodites (monoecious / bisexual). Cockroach is a dioecious (unisexual) species having distinct male and female individuals.

Placenta also acts as an endocrine tissue and produces several hormones like human chorionic gonadotropin (hCG), human placental lactogen (hPL), estrogens, progestogens, and relaxin.

Luteinising hormone (LH) is secreted by the anterior pituitary gland, not by the placenta.

Analysis of statements:

• Incorrect: The first menstruation beginning at puberty is called menarche (menopause is the permanent cessation).
• Incorrect: Ovulation at mid-cycle (14th day) is induced by the LH surge (rapid secretion of LH), not maximum progesterone (progesterone peaks during the luteal phase around day 20-22).
• Correct: In the absence of fertilization, the corpus luteum degenerates, progesterone levels plummet, causing endometrial breakdown and menstruation.
• Correct: Menstrual cycles cease around 50 years of age, which is termed menopause.

The human placenta functions as a temporary endocrine gland producing hormones such as:

• Human chorionic gonadotropin (hCG)
• Human placental lactogen (hPL)
• Estrogens and Progestogens
• Relaxin (secreted in later stages)
  
  Androgens (male sex hormones like testosterone) are produced by the Leydig cells of the testes and adrenal cortex, not by the placenta.