Thylacosmilus is a marsupial, and Smilodon is a mammal. Thylacosmilus and Smilodon both have saber teeth, but they do not share an ancestor that had saber teeth. What are saber teeth for these organisms?1. anlogous structures2. homologous structures3. vestigial structures4. mutated structures

1. Analogous structures.

Explanation:

Analogous structures are defined as similar structures which evolved independently to perform same kind of work in two different organisms. In short we can say that analogous structures are not derived from same ancestor both the individuals having these structures developed them independently.

Convergent evolution best defines concept of analogous structures.

Another classical example of analogous structures is wings in birds and insects. Wings look similar and perform same function in both the organisms but their origin is not same i.e. birds and insects do not share common ancestor which had wings leading to the conclusion that they both developed wings independently.

what statement best describes the difference between the sympathetic and parasympathetic nervous systems?

the sympathetic nervous system prepares the body for intense physical activity and is often referred to as the fight-or-flight response. the parasympathetic nervous system has almost the exact opposite effect and relaxes the body and inhibits or slows many high energy functions.