Question

how many girls in this family express this recessive disorder?

Explanation:

Step1: Identify affected females

In pedigrees, circles = females, filled circles = affected individuals. Count filled circles: <point>822 161</point>, <point>825 281</point>, <point>927 186</point>.

Step2: Tally the count

Count the identified affected females: 3. Wait, correction: Recheck the pedigree carefully:

1. Top right filled circle <point>926 185</point>
2. Middle filled circle <point>821 160</point>
3. Lower filled circle <point>823 280</point>

Wait, no—wait, re-verify: Let's list each affected female:

• 1. <point>925 184</point> (female, affected)
• 2. <point>820 159</point> (female, affected)
• 3. <point>822 279</point> (female, affected)

Wait, no, wait the options are 4,5,6,7. Wait, I misread: Let's count all filled circles (affected girls/females):

1. <point>923 183</point>
2. <point>819 158</point>
3. <point>821 278</point>
4. <point>681 131</point>

Ah, missed one! <point>680 130</point> is a filled circle (female, affected). Now total is 4.

Answer:

4