Explanation

• Gonyaulax is a marine dinoflagellate commonly associated with red tides, which occur when certain microscopic algae multiply rapidly in seawater.
• Red tides can discolor seawater reddish-brown.
• It may release toxins that harm fish, shellfish, and other marine organisms.

Last verified on 27-10-2026

Explanation

• Plasmids are small, usually circular DNA molecules found mainly in bacteria, separate from the bacterial chromosome.
• They replicate independently and may carry genes that provide advantages, such as antibiotic resistance.

Last verified on 27-10-2026

Explanation

• Riccia is a simple liverwort belonging to the bryophytes.
• Its sporophyte is highly reduced and consists mainly of a capsule embedded in the gametophyte.
• In Riccia, the capsule lacks a well-developed seta and elaters.
• The spores are released when the surrounding gametophytic tissue decays.

Last verified on 27-10-2026

Explanation

• The carinal canal forms due to the disintegration of protoxylem elements in the stem of Equisetum (horsetail).
• It is located within each vascular bundle, beneath the ridge of the stem.
• The vallecular canals are different cavities located beneath the grooves of the stem.
• They are associated with the cortex.

Last verified on 27-10-2026

Explanation

• Silverfish is a small, wingless insect belonging to the phylum Arthropoda and class Insecta.
• It has a flattened, elongated body covered with silvery scales and three tail-like appendages.

Last verified on 27-10-2026

Explanation

• Gene cloning is a technique used to produce multiple identical copies of a specific gene or DNA sequence.
• The cloned gene can be introduced into host cells, which multiply and produce copies of the desired DNA.

Last verified on 27-10-2026

Explanation

• Tropical rain forests support exceptionally high biodiversity but face severe threats from deforestation, agricultural expansion, logging, and habitat destruction.
• Subtropical rain forests are also threatened by habitat loss, land conversion, and human activities.

Last verified on 27-10-2026

Explanation

• Cichlids are freshwater fish found in several lakes, including Lake Victoria in Africa, which is famous for its diverse cichlid species.
• Overfishing, waste pollution, and agricultural runoff can damage aquatic ecosystems and contribute to the decline or extinction of fish species.
• Agricultural runoff may carry fertilizers and pesticides into lakes, causing eutrophication, reducing oxygen levels, and harming aquatic life.

Last verified on 27-10-2026

Explanation

• Sergei Nawaschin discovered double fertilization in flowering plants (angiosperms) in 1898.
• In double fertilization, one male gamete fuses with the egg cell to form a diploid zygote (2n), while the other fuses with the two polar nuclei to form the triploid endosperm (3n) in typical angiosperms.
• The zygote develops into the embryo, while the endosperm provides nourishment to the developing embryo.

Last verified on 27-10-2026

Explanation

• The Stark effect is the splitting or shifting of spectral lines of atoms or molecules due to an external electric field.
• The Stark effect is named after German physicist Johannes Stark, who discovered it in 1913.

Additional information:

• The Zeeman effect is the splitting of spectral lines due to an external magnetic field.
• The Photoelectric effect occurs when light ejects electrons from a material.

Last verified on 27-10-2026