Question

the circled portion contains three chromosomes. what is the total chromosome number for this organism?
25 pairs
24
47
45

Explanation:

Step1: Analyze Chromosome Pairs

Most organisms have chromosomes in pairs, except for a possible extra (like trisomy). Normal human has 23 pairs (46), but here one pair (circled) has 3 (trisomy), others are pairs. Let's count: 22 pairs (44) + 3 (from the trisomic pair) = 47? Wait, no—wait, the circled is one set: normally pairs (2 per pair), but here 3. Let's check the options. Wait, the image shows chromosomes: let's count the total. Wait, the circled (chromosome 6) has 3, others: let's see the number of chromosomes. Wait, the options: 47? Wait, normal is 46, but if one pair has 3 (trisomy), total is 47? Wait, no—wait, the problem: the circled portion (one "pair" but with 3) and others. Let's count the total chromosomes. Let's see the rows:

First row (1 - 5): 5 chromosomes (but maybe pairs? Wait, no, the numbering: 1,2,3,4,5 (maybe 5 pairs? No, 1-22 are autosomes, 23 is sex). Wait, the circled is chromosome 6 with 3. So total chromosomes: normally, each pair has 2, but one pair has 3. So total pairs: 22 pairs (44) + 3 (from the trisomic pair) = 47? Wait, but let's check the options. The options are 25 pairs, 24, 47, 45. Wait, 22 pairs (44) + 3 (trisomy) = 47. So the correct answer is 47.

Step2: Match with Options

The option 47 is present. So the total chromosome number is 47.

Answer:

47