Chapter 31, Problem 8STP

Summary Introduction

Introduction:

Dinosaurs belong to a large group of reptiles called Archosauria. They are classified into two different orders.

1. Ornithischia or bird-hipped dinosaurs.
2. Saurischia or lizard-hipped dinosaurs.

Answer to Problem 8STP

Correct answer:

The correct answer is option (a) Structure of their hipbone.

Explanation of Solution

Explanation/justification for the correct answer:

Option (A) Structure of the hipbone of the Dinosaurs divides them into two parts. The hipbone structure of one dinosaur is like Bird-hipped, whereas the hipbone structure of another dinosaur is like lizard-hipped. Hence the dinosaurs that come under reptilians are distinguished between these two groups depending upon the structure of the hipbone.

Explanation for incorrect answer:

Option (B) Structure of the skull and Jaw isn’t a correct option as the skull of all dinosaur was believed to have a hole between the eye socket and nostril.

Option (C) As per the researches, dinosaurs grew fast. This characteristic doesn’t resemble a mammal or a reptile and so they don’t come under either ectotherms or endotherms. Dinosaurs are said to come under somewhere in the middle of these two, known as mesotherms.

Option (D) Dinosaurs were not necessarily herbivores (plant eater) or carnivores (flesh eater). They were omnivores too (eating both).