Tall (T) is dominant over dwarf (t) in a species of plant. A tall plant has an unknown genotype. Which plant should it be crossed with to ascertain this?

• TT

• Tt

• tt

Sperms can have

• Only X chromosome

• Only Y chromosome

• Either X or Y chromosome

• Either XX or XY chromosomes

Ova (eggs) can have

• Only X chromosome

• Only Y chromosome

• Either X or Y chromosome

• Only XX chromosomes

What is the percentage of a woman having a male child?

• 25%

• 50%

• 75%

• 100%

A couple has 6 children but of them, 5 were boys. What reason explains why this deviates from the expected 3 boys : 3 girls ratio?

• The female suffers from a genetic disorder.

• The male only release sperms with the Y chromosome.

• The sample size is too small.

• The correct ratio is actually 5:1. There is nothing wrong.

A brown eyed man of genotype Bb marries a blue eyed woman. What is the chance that their third child is brown eyed?

• 25%

• 50%

• 75%

• 100%

A couple has had 1 child, who is a boy. Which of the following statements is true?

• Their second child will be a girl because the ratio of boy:girl is 1:1.

• Their second child will be definitely be a girl because the chance of her being a girl is 50%.

• Their second child has a 50% chance of being either a boy or a girl as gender of the first child has no effect on the subsequent children.

A rose species has color which is determined by alleles R and r. A genotype of RR will give rise to red coloration, while rr gives rise to white coloration. Which of the statements is false?

• The alleles R and r are different forms of a gene.

• A gene is made up of proteins.

• A gene consists of a DNA sequence.

• The heterozygous genotype will have a phenotype of red.

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

Which of the following traits exhibit discontinuous variation?

• weight

• IQ (intelligence quotient)

• skin colour

• left or right handedness

Somatic cells have 46 chromosomes. A boy's somatic cells would have ______

• 46 identical chromosomes of identical length.

• 46 chromosomes of varying length.

• 22 pairs of different chromosomes, but each pair is of the same length; one X and one Y chromosome.

• 22 pairs of different chromosomes, but each pair is of the same length; and two X chromosomes.