Question

1. two traits were observed for hamsters: color and tail length. for color, black (b) is dominant over tan (b). for tail length, short tails (s) are dominant over long tails (s). what is the genotype for a heterozygous black short - tailed hamster? options: bbss, bbss, bbss, bbss (with a clear all button)

Explanation:

Step1: Analyze color genotype

Black (B) is dominant, heterozygous means one dominant and one recessive allele, so for color: \( Bb \).

Step2: Analyze tail length genotype

Short tails (S) are dominant, short - tailed and since we need to consider the genotype, short - tailed can be homozygous or heterozygous? Wait, no, the hamster is short - tailed. But let's re - read: the hamster is heterozygous black (so \( Bb \)) and short - tailed. For short tails, dominant is S. But what's the genotype for short tail? Wait, the question is about heterozygous black and short - tailed. Wait, no, the options: let's check the options. The hamster is heterozygous black (so \( Bb \)) and short - tailed. Short tails: dominant is S. If it's short - tailed, and we need to see the genotype. Wait, the options have Bb and then for tail: let's see the options. The correct genotype should be \( Bb \) for color (heterozygous) and for tail, short - tailed. Wait, the options: BbSs? Wait no, wait the options are: BBSS, Bbss, BbSS, BBSs. Wait, no, wait the question is heterozygous black (so \( Bb \)) and short - tailed. Short tails: S is dominant. So for tail length, short - tailed can be SS or Ss? Wait, no, the hamster is short - tailed. But the key is heterozygous black ( \( Bb \)) and short - tailed. Wait, maybe I misread. Wait, the problem says "heterozygous black short - tailed hamster". So black is heterozygous: \( Bb \), short - tailed: let's see the options. Wait, the options: BbSs? No, the options are BBSS, Bbss, BbSS, BBSs. Wait, no, maybe I made a mistake. Wait, black is dominant (B) over tan (b). Heterozygous black means \( Bb \). Short tails (S) are dominant over long tails (s). Short - tailed: so the tail genotype. If it's short - tailed, and we need to find the genotype for heterozygous black and short - tailed. Wait, the options: let's check each option. Option BbSs: no, the options given are BBSS, Bbss, BbSS, BBSs. Wait, no, maybe the original problem's options are different? Wait, no, the user's image: the options are (from left to right, maybe? Wait, the options are: first option BBSS, second Bbss, third BbSS, fourth BBSs. Wait, no, maybe I misread the tail length. Wait, the hamster is short - tailed. Short tails are dominant (S), so short - tailed can be SS or Ss. But the hamster is heterozygous black ( \( Bb \)) and short - tailed. So the genotype should be \( Bb \) for color and for tail, since it's short - tailed, and looking at the options, BbSS? Wait, no, BbSS: \( Bb \) for color (heterozygous) and SS for tail (homozygous short - tailed). Wait, but maybe the short - tailed is homozygous? Wait, no, the question is heterozygous black and short - tailed. Wait, maybe I made a mistake. Wait, let's re - evaluate. Heterozygous black: \( Bb \). Short - tailed: S is dominant. So the genotype should be \( Bb \) (for color) and for tail, since it's short - tailed, let's see the options. The option BbSS: \( Bb \) (heterozygous black) and SS (homozygous short - tailed). Wait, but is that correct? Wait, no, maybe the tail is Ss? But the options don't have BbSs. Wait, maybe the problem has a typo, or I misread. Wait, the options given: BBSS (homozygous black, homozygous short - tailed), Bbss (heterozygous black, homozygous long - tailed? No, ss is long - tailed), BbSS (heterozygous black, homozygous short - tailed), BBSs (homozygous black, heterozygous short - tailed). Wait, the hamster is heterozygous black (so \( Bb \)) and short - tailed (so S_). So the correct genotype is \( Bb \) (for color) and SS (for tail, since it's short - tailed and the options have BbSS). Wait, but why SS? Because if it's short - tailed, and we need to match the options. So the correct option is BbSS? Wait, no, wait the options: let's check the problem again. The question is "heterozygous black short - tailed hamster". Heterozygous black: \( Bb \). Short - tailed: S is dominant, so the tail genotype should have at least one S. So among the options, BbSS: \( Bb \) (heterozygous black) and SS (homozygous short - tailed). Bbss: \( Bb \) but ss is long - tailed, so no. BBSS: homozygous black, so no. BBSs: homozygous black, heterozygous short - tailed. So the correct one is BbSS? Wait, no, maybe I messed up. Wait, heterozygous black is \( Bb \), short - tailed: S is dominant. So the genotype is \( Bb \) (for color) and for tail, since it's short - tailed, and the options, the only one with \( Bb \) and short - tailed (SS or Ss) is BbSS (since Bbss is long - tailed, BBSs is homozygous black, BBSS is homozygous black). So the correct option is BbSS? Wait, no, the options are BbSS (third option). Wait, maybe I made a mistake in the tail genotype. Wait, short - tailed: S is dominant, so SS or Ss. But the options don't have Ss, so it must be SS. So the genotype is \( BbSS \).

Answer:

BbSS (the option corresponding to heterozygous black (\( Bb \)) and homozygous short - tailed (\( SS \)))