Which of the following statements best describes how Mendel eliminated any uncertainty from his experiments?
He performed a large number of crosses over many years.
He studied the trait of height, which could be measured easily.
He studied a wide variety of traits, such as flower colour, shape of pea, height of stem.
He carefully transferred pollen from one pea plant to the reproductive parts of another.
Which option correctly completes the sentence below?
The segregation of alleles occurs during _________ in eukaryotic organisms
Mitosis
Binary fission
Meiosis
DNA replication before cell division
Which of the following statements correctly describes co-dominance?
The alleles are both expressed to an equal extent in the phenotype.
Two alleles are 'blended together'.
One allele is dominant over the other.
Neither allele is expressed in the phenotype.
Which of the following statements is a feature of X-linked genetic diseases in humans?
Females can’t inherit the defective gene as they don’t possess a Y chromosome.
Females can either be normal, a carrier or have the disease.
Males can be a carrier for the defective allele.
Females can only be heterozygous for the defective gene.
Which of the following statements correctly describes the consequences of the Chernobyl nuclear accident in 1986?
I. Concentrations of radioactive iodine in the environment increased.
II. There was a large increase in the reported cases of thyroid cancer.
III. Horses and cattle near the nuclear power plant died due to damage to their thyroid glands.
IV. The effects of the disaster were localised to the immediate area.
I and II only.
I, II and III.
III and IV only
I, II, III and IV.
