Which of the following animal groups correctly matches its characteristic without any exceptions?

Which fish gives birth to young ones?

Heterocercal tail is found in

The Ampulla of Lorenzini in fishes is a:

Which one of the following groups of animals is correctly matched with its characteristic feature without any exception?

Which of the following statements are not true about shark?
$a$. The skin is tough and covered with placoid scales
$b$. They possess a swim bladder which regulates buoyancy
$c$. The tail of shark is heterocercal
$d$. Ampulla of Lorenzini present in the snout of shark is a thermoreceptor.
$e$. It has five pairs of gill slits covered by operculum