Final answer:
The traits listed—body covered in hairs, hairs modified into spines, short limbs, and four walking limbs—are all homologous traits as they suggest a common ancestry among the organisms that exhibit them. Therefore, option b) 1. Homologous, 2. Homologous, 3. Homologous, 4. Homologous is the correct categorization for these traits.
Step-by-step explanation:
When identifying traits within organisms, scientists must determine whether the traits are homologous or analogous. They are derived from a common ancestor and indicate genetic relatedness. This similarity is based on shared embryonic development.
On the other hand, analogous traits serve a similar function but evolved independently, usually because of similar environmental pressures and adaptive needs, not due to common ancestry.
Given the characteristics listed in the question:
- Body covered in hairs
- Hairs modified into spines
- Short limbs
- Four walking limbs
The correct categorization for these traits would be:
Homologous: Body covered in hairs are characteristic of mammals, derived from a common ancestor.
Homologous: Hairs modified into spines are specific developments within certain groups of mammals, indicating a shared evolutionary origin.
Homologous: Short limbs can be a homologous trait if they stem from a common ancestor within a group of organisms with such a limb structure.
Homologous: The presence of four walking limbs is a feature seen in tetrapods (four-limbed vertebrates), which is a homologous trait originating from a common ancestor.
Therefore, the correct categorization for each trait is b) 1. Homologous, 2. Homologous, 3. Homologous, 4. Homologous.