Question

Marchantia is considered heterothallic because it is
A. Heterogametic
B. Bisexual
C. Monoecious
D. Dioecious

Answer 1

Hint: Marchantia is dioecious, therefore, it is considered heterothallic. This means It has two distinct male and female plants. The antheridiophores on male plants give birth to antheridia while the archegoniophores on the female plant give birth to archegonia. The sporophyte gives rise to spores which develop into free-living male and female.

Complete answer:
Option A- Heterogametic
Heterogantic is the species in which the sex chromosomes are not the same. For example, in humans, males, have an X and a Y sex chromosome, therefore, they are referred to as the heterogametic sex, and females have two X sex chromosomes, therefore, they are referred to as as the homogametic sex.

Option B- Bisexual
According to biology, Bisexuality is the condition of an organism capable of producing both male and female gametes (sex cells). In plants and microorganisms, this condition is called monoecism. In multicellular animals, this is usually called hermaphroditism.

Option C- Monoecious
Species that bear both sperm and eggs on the same gametophyte are known as Monoecious. Whereas, plants that have gametophytes that produce only sperm or eggs but never both are known as dioecious.

Option D- Dioecious
Also known as Dioecy. It is a characteristic of a species that has distinct male and female individual organisms. Also, Dioecious reproduction is biparental reproduction.

So, the correct answer is option D - Dioecious.

Note: Marchantia is a genus belonging to the family Marchantiaceae and order Marchantiales. It is a group of liverworts. The Marchantia shows a characteristic feature i.e differentiation into two layers: an upper photosynthetic layer which has a well-defined upper epidermis with pores and a lower storage layer.