Assertion: Polytene chromosomes have a high amount of DNA.
Reason: Polytene chromosomes are formed by repeated replication of chromosomal DNA without separation of chromatids.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
A.
If both assertion and reason are true and reason is the correct explanation of assertion
Polytene chromosomes are quite common in salivary glands of insects and so are called salivary chromosomes. These chromosomes have high amount of DNA of almost I 000 times in Drosophila as compared to ordinary somatic chromosomes. These chromosomes are multistranded. They are in permanent prophase stage. These chromosomes& are formed by somatic pairing between homologous chromosomes and repeated replication pf their chromonemata without separation of chromatids. All the chromosomes may remain attached to one another at a common point called chromocentre.
Assertion: The earliest organisms that appeared on the Earth were non-green and presumably anaerobes.
Reason: The first autotrophic organisms were the chemoautotrophs that never released oxygen.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
Assertion: Deforestation is one main factor contributing to global warming.
Reason: Besides CO2, two other gases methane and CFCs are also included under green house gases.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
Assertion: UV radiation causes photodissociation of ozone into O2 and O3 thus causing damage to the stratospheric ozone layer.
Reason: Ozone hole is resulting in global warming and climate change.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
Assertion: The concentration of methane in the atmosphere has more than doubled in the last 250 years.
Reason: Wetlands and rice fields are the major sources of methane.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
Assertion: Inflammation of a skeletal joint may immobilize the movements of the joint.
Reason: Uric acid crystals in the joint cavity and ossification of articular cartilage lead to this
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
Assertion: In tropical rain forests, O-horizon and A-horizon of soil profile are shallow and nutrient-poor.
Reason: Excessive growth of micro-organisms in the soil depletes its organic content.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
Assertion: LSD and marijuana are clinically used as analgesics.
Reason: Both these drugs suppress brain function.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
Assertion: An organism with lethal mutation may not even develop beyond the zygote stage.
Reason: All types of gene mutations are lethal.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
Assertion: Escherichia coli, Shigella sp. and Salmonella sp. are all responsible for diarrhoeal disease.
Reason: Dehydration is common to al I types of diarrhoeal diseases and adequate supply of fluids electrolytes should be ensured.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.