Question

a heterozygous long-tusked elephant is crossed with a homozygous recessive short-tusked elephant. what is the probability of the offspring having short tusks?
75%
50%
0%
25%

Explanation:

Step1: Define allele notation

Let $L$ = dominant long-tusk allele, $l$ = recessive short-tusk allele.

Step2: Identify parent genotypes

Heterozygous long-tusked elephant: $Ll$; Homozygous recessive short-tusked elephant: $ll$.

Step3: Set up Punnett square

	$L$	$l$
$l$	$Ll$	$ll$

Step4: Calculate short-tusk probability

Short tusks require $ll$. 2 out of 4 genotypes are $ll$.
$\text{Probability} = \frac{2}{4} = 50\%$

Answer:

B. 50%