How are the autotrophic protists different from the heterotrophic protists?
a. the autotrophic protists can photosynthesize, while the heterotrophic protists cannot.
b. the heterotrophic protists can all move around, while the autotrophic protists are immobile.
c. the heterotrophic protists reproduce by spores, while the autotrophic protists form eggs.
d. the autotrophic protists eat by endocytosis, while the heterotrophic protists use pinocytosis.

I think the correct answer from the choices listed above is option A. Autotrophic protists are different from the heterotrophic protists in a sense that the autotrophic protists can photosynthesize, while the heterotrophic protists cannot. Hope this answers the question.

The right option is; A. The autotrophic protists can photosynthesize, while the heterotrophic protists cannot.

Protists are eukaryotic, microscopic organisms that may be unicellular or multicellular. In terms of feeding, some protists are autotrophic while some are heterotrophic. The difference between them is that the autotrophic protists produce their own food through the process of photosynthesis, while the heterotrophic protists cannot photosynthesize but they obtain their food by ingesting other organisms or decaying organic matter.

NO, I do not recall any vertebrates with external reproductive organs on their dorsal surface.

Explanation:

Usually the urogenital systems in vertebrate includes a combination of reproductive and excretory tissues. And it is a very common feature in vertebrates.

Disadvantages:

Urine would flow over the body surface if the external reproductive organs on their dorsal surface.They are more prone to be damaged by the environment. as the ventral surface provides more protection.

Advantage:

Higher coverage: Posterior placement provides this advantage due to back to back mating.