Tag: biology

Canal irrigation was started in 1960, these are human-made channels for water transportations. India has the largest canal system starting for Harike Barrage and terminates in irrigation facilities in the Thar Desert, it is known as The Indira Gandhi Canal. Now, canal irrigation is 2nd largest source of water transportation in the world.

Bt cotton is modified in such a way that it is resistant to insects and pests. It has inactive protein being produced which gets activated once entering the gut of insect and killing them.

Ectocarpus is a brown alga (Phaeophyceae) in which food is stored in the form of complex carbohydrates such as laminarin and mannitol. Volvox stores food as starch, and Marchantia is a bryophyte.

Cephaleuros is a well-known genus of parasitic green algae, specifically causing red rust of tea. The other genera listed are free-living aquatic algae.

Anabaena is a genus of filamentous cyanobacteria, which are prokaryotes and therefore lack a true membrane-bound nucleus. The other options are eukaryotes with true nuclei.

Archegonia are female reproductive organs found in bryophytes, pteridophytes, and gymnosperms. Spirogyra is an alga and does not produce archegonia.

Ulothrix reproduces via zoospores or isogamy/anisogamy, not heterocysts. Heterocysts are specialized cells found in certain cyanobacteria like Nostoc or Anabaena for nitrogen fixation.

Estrogens are produced primarily by the ovaries. They are released by the Graafian follicles on the ovaries and are also secreted by the corpus luteum after the egg has been released from the follicle and from the placenta. 

Estrogen is the female sex hormone which is secreted by developing follicles in the ovary. Secretion of gonadotropins during the follicular phase of ovarian cycle stimulate growth and development of follicles. These developing follicles secrete estrogen. Thus, the correct answer is option C.