Hint Cleidoic eggs constitutive protective shell which is laid out of the water and is porous to air. This shell is calcareous and may be flexible. It consists of the food that the embryo needs to develop into hatching.
Cleidoic eggs are the characteristics of reptiles, birds, and insects. Birds are warm-blooded vertebrates that live in diverse habitats and migrate to warmer countries whenever the weather changes. They have various adaptive features that help them to fly which include the presence of feathers. Birds have adapted themselves with air sacs and feathers that make them adapt to the aerial mode of life. Reptiles are the vertebrates that are covered in a special skin that is made up of scales and bony plates with the combination of both and includes certain tortoises, snakes, lizards, crocodiles. they shed their outer layer of the skin and their metabolism depends upon the temperature of the surroundings. Insects are the arthropods which comprise a chitinous exoskeleton and a three-part body including the head, thorax, and abdomen with compound eyes and a pair of antennae.
Mammals: It is a group of vertebrate animals that are characterized by the presence of mammary glands. The females produce milk for feeding their young ones through the mammary glands which are known as nursing. They contain the neocortex which is a region of the brain and three middle ear bones. In cladistics, the mammals are the only living members of the Synapsida which constitutes the reptiles and birds. They have the quadruped body type and are used for their terrestrial locomotion. They can live from 2 years to 211 years. The species of mammals that are the placentals are the richest which enable the feeding of foetus during the gestation period.
Insects only: Insects hatch from eggs and are constrained by the inelastic exoskeleton which develops and involves a series of moults. The adult stage and the in which state are distinct and include a passive pupal stage which undergoes a four-stage metamorphosis.
Fishes: They constitute gills for respiration and lack limbs with digits. They can communicate underwater through the use of acoustic communication in which the transmission of acoustic signals from one individual of species to another takes place and the production of sound is used in the context of feeding, courtship behavior, and aggression. They all are aquatic and exhibit diversity in species and an important resource for humans especially food.
So, the correct answer is 'Reptiles, birds, and insects'.
Note: Cleidoic eggs help in the reproduction away from the water and is an important characteristic of birds and reptiles. The nutrients water and minerals required by the embryo are enclosed within the cleidoic egg and the exchange of gases occurs between the inside and outside of the egg.