Blended and both-showing traits

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. 1.

   Esme reads a model square for a roan parent crossed with a red parent. Which genotype fills the top-right box?

   • W (one white allele)
   • RR (two red alleles)
   • WW (two white alleles)
   • RW (one red and one white allele)

2. Read this first

   A snapdragon cross (model)

   plant	genotype	flower color
   red parent	RR	red
   white parent	WW	white
   offspring	RW	pink

3. 2.

   Jun reads a snapdragon cross card. Which pattern does it show?

   • Codominance: both alleles show side by side
   • Complete dominance: one allele hides the other allele
   • Blending: the alleles mix and stay mixed
   • Incomplete dominance: the offspring look in between the parents

4. A cattle cross (model)

   animal	genotype	coat
   red parent	RR	all red hairs
   white parent	WW	all white hairs
   offspring	RW	red hairs and white hairs together

5. 3.

   Kira reads a model cattle cross card. Which word describes the offspring coat?

   • Segregation: the alleles split into two groups
   • Incomplete dominance: one mixed color between the parents
   • Complete dominance: the red allele hides the white allele
   • Codominance: both alleles show at the same time

6. A pea flower cross (model)

   plant	genotype	flower color
   parent one	VV	violet
   parent two	vv	white
   offspring	Vv	violet

7. 4.

   Luz reads a pea cross card. Which pattern does it show?

   • Codominance: Vv shows violet and white patches
   • Incomplete dominance: Vv looks in between the parents
   • Complete dominance: V hides v, so Vv looks violet
   • Blending: the colors mix, so Vv should look pale

8. Three cattle coats (model)

   genotype	coat	hairs
   RR	red coat	all red hairs
   RW	roan coat	red hairs and white hairs mixed
   WW	white coat	all white hairs

9. 5.

   Milo reads a model coat card. A calf has genotype RW. What do its hairs look like?

   • White hairs alone, because W hides R
   • Red hairs alone, because R hides W
   • Red hairs and white hairs, mixed together
   • Pink hairs, a blend of red and white

10. Hairs counted on one roan calf (model data)

    hair color	hairs counted
    red	52
    white	48
    pink	0

11. 6.

    Noah counts 100 hairs on a roan calf. What does the count show?

    • Red is dominant, since 52 is more than 48
    • Each hair is red or white, and none is pink
    • Some red hairs faded to white over time
    • Each hair is a pink blend, since 52 and 48 are close

12. Three snapdragon plants (model)

    plant	flower color
    X	red
    Y	pink
    Z	white

13. 7.

    Pia reads a snapdragon card. Plant Y has pink flowers. Which genotype does it have?

    • R (a single red allele)
    • RR (two red alleles)
    • WW (two white alleles)
    • RW (one red and one white allele)
14. 8.

    Ren reads the filled square for two pink snapdragons. Which list matches the four boxes?

    • 1 red, 2 pink, 1 white
    • 2 red, 2 white
    • 4 pink, since both parents are pink
    • 3 red or pink, 1 white
15. 9.

    Tala reads a model square for two roan parents. How many of the four boxes show a roan calf?

    • 2 of 4, the two RW boxes
    • 4 of 4, since both parents are roan
    • 1 of 4, the single RW box
    • 3 of 4, as in a 3 : 1 cross
16. 10.

    Zee reads the filled square for two pink snapdragons. It shows a white flower. Why is that possible?

    • The white allele was lost, so the square must be wrong
    • Each pink parent carries a white allele and can pass it on
    • The red allele fades to white in some boxes
    • Pink parents give pink offspring, so the white box is an error