Explanation

Actinopods are a group of protists that use specialized pseudopodia, called axopodia, for locomotion and capturing food. 

Explanation

 The digestive system in animals develops primarily from the endoderm, with contributions from the mesoderm for certain structures.

The ectoderm plays a role in the development of the mouth and anus.

Explanation

Blubber is a thick layer of fatty tissue found under the skin of whales, seals, and other marine mammals.

It acts as insulation against cold temperatures in ocean water and also serves as an energy reserve.

Explanation

The organism found in the gut of termites that helps them digest wood is a protozoan called Trichonympha

These protists break down cellulose in wood, allowing termites to digest it effectively. 

Explanation

Sharks belong to the class Chondrichthyes, which includes cartilaginous fishes.

Explanation

 "Colony" is the correct collective noun for ants

While "colony" is the most common term, "army" 

Explanation

 The trochophore larva is a characteristic larval stage found in several marine invertebrates.

Most notably within the phyla Annelida (segmented worms) and Mollusca (mollusks).

It is also present in other groups within the superphylum Lophotrochozoa, including entoprocts, nemerteans, echiurans, and sipunculans. 

Explanation

Explanation

For deep-sea diving, oxygen is mixed with helium (forming heliox) to prevent nitrogen narcosis and oxygen toxicity at high pressures.

Helium is inert, light, and doesn't cause narcotic effects under pressure like nitrogen does.

Explanation

Assuming the context is biological diversity or several species, the correct descending order would be based on the number of species in each group:

Insects: ~1 million+ species

Fish: ~34,000 species

Reptiles: ~11,000 species

Mammals: ~6,400 species