Question

Monoecious plant of Chara shows the occurrence of
A. Antheridiophore and archegoniophore on the same plant.
B. Stamen and carpel on the same plant.
C. Upper antheridium and lower oogonium on the same plant.
D. Upper oogonium and lower antheridium on the same plant.

Answer 1

Hint: Within the Characeae family, Chara is a genus of green algae. The stem-like and leaf-like structures are multicellular and superficially resemble land plants. Owing to stem-like and leaf-like structures, they resemble land plants superficially. In freshwater, they are mainly found.

Complete answer: Chara is a green algae genus. They are multicellular and resemble land plants superficially. They need less harsh and oxygenated water. They are coated with layers of calcium carbonate and are popularly known as stoneworts.
-In both sexual and vegetative phases, Chara reproduces. An advanced oogamous form is the sexual reproduction of Chara. Such sex organs are large and macroscopic. The male sex organ, called the globule, is yellow to red in colour. The female sex organ, called nucule or oogonium, is more or less oval and green in colour. On maturity, antheridia filaments made up of antheridium cells grow into globules. Oogonium is often found separately above the antheridium or globule.
-Plenty of the species are homothallic or monoecious (i.e. on the same plant, male and female sex organs develop), although some are heterothallic or dioecious (i.e. on multiple plants, male and female sex organs).
-The zygote grows into an oospore after fertilization. They are found in water, particularly in calcareous areas in the northern temperate region, where they grow underwater, connected to the muddy bottom. The body of the plant is a gametophyte. It comprises the main axis (differentiated into nodes and internodes), the dimorphic branches (the long limitless growth branch and the short-limited growth branch), the rhizoids (the oblique septal multicellular branch), and the stipulodes (the needle-shaped structures at the base of the lateral secondary branch).
 Thus, choice D, i.e., Upper oogonium and lower antheridium on the same plant is the correct one.

Note: Chara are coated with layers of calcium carbonate and are generally referred to as stoneworts. Mostly on surfaces of Chara, where they will be active in fixing nitrogen, which is essential for plant nutrition, cyanobacteria are seen emerging as epiphytes.