Heterocyst-forming Cyanobacteria differentiate highly specialized cells to provide fixed nitrogen to the vegetative cells in a filament.
Answer: during the course of infection the parasite, Giardia lamblia, pass through many anatomical locations to achieve its pathogenic effects which occurs in one host.
Explanation: infective form of the parasite is the mature cyst. Infection is acquired through ingestion of cysts in contaminated water or food. From the mouth the cyst passes down to the duodenum where it undergoes excystation. The cyst hatches out two trophozoites. By means of concavity on its ventral surface the trophozoites attaches to the epithelial lining of the small intestines. Encrustation occurs commonly in transit down the colon. Trophozoites retract the flagella into the axonemes, the cytoplasm becomes condensed and a thin tough hyaline cyst wall is secreted. As the cyst matures, the internal structures are doubled, so that when excystation occurs, the cytoplasm divides thus reproducing two trophozoites. Trophozoites are expelled through the anus with diarrhoeal stools.
<span>Platelets - help the blood to clot. Clotting stops the blood from flowing out of the body when a vein or artery is broken.
Red blood cells - carry oxygen
White blood cells - ward off infection</span>
The right option is Capsid
A capsid is a protein coat that
encloses the nucleic acid (RNA, DNA etc.) of a virus particle. Capsids are in different
shapes and the common ones are icosahedral, prolate, and helical. The main role
of the capsid is to protect the virus by ensuring that the nucleic acid inside
of it is safe.
