Given below are two statements: Statement I: RNA mutates at a faster rate. Statement II: Viruses having RNA genome and shorter life span mutate and evolve faster.
In the light of the above statements, choose the correct answer from the options given below
Given below are two statements: Statement I: In prokaryotes, the positively charged DNA is held with some negatively charged proteins in a region called
nucleoid. Statement II: In eukaryotes, the negatively charged DNA is wrapped around the positively charged histone octamer to form nucleosome.
In the light of the above statements, choose the correct answer from the options given below:
Select the correct group/set of Australian Marsupials exhibiting adaptive radiation.
AI-generated explanation. Check against your textbook.
Explanation:
Option 3 is correct. In Australia, marsupials radiated into many forms to fill different ecological niches. Numbat (insectivore), Spotted cuscus (arboreal herbivore), and Flying phalanger (gliding omnivore) show diverse lifestyles, illustrating adaptive radiation within a single lineage in a shared environment.
๐ง Did You Know?
Australian marsupials evolved after Australia separated from other landmasses, leading to unique adaptations not seen in placental mammals of other continents.
๐ก NCERT Memory Line:
Australia is a classic example of adaptive radiation of marsupials into diverse forms to occupy different ecological niches.
In which blood corpuscles, the HIV undergoes replication and produces progeny viruses?
AI-generated explanation. Check against your textbook.
Explanation:
HIV targets CD4+ T-lymphocytes (T helper cells). Inside these cells, the virus uses the cellular machinery to replicate and produce progeny virions, eventually destroying the T cells and weakening the immune response. Thus, HIV replication occurs in TH cells, not in other blood cells listed.
๐ง Did You Know?
HIV specifically infects T helper (TH) cells and uses them for replication, leading to AIDS if untreated.
๐ก NCERT Memory Line:
HIV attacks CD4+ T-lymphocytes (T helper cells) and uses them for replication.
