Abdomen
Yes. As part of a definition of an insect, an insect is a creature from the Animal kingdom with six legs, three major body sections (head, thorax, and abdomen), and antannae.
Thorax
The arthropod body plan has a great deal to do with how they are classified. Insects are hexapods with three body sections, a head, consollidated thorax with three leg pairs, and an abdomen. The chelicerates, like arachnids, have two main body sections and eight legs. Myriapods have up to hundreds of sections each with a leg pair. Many crustaceans are decapods, have ten legs, often a fused cephalothorax and articulated abdominal segments like lobsters, crayfish, shrimp, prawns and krill; similar is true of crabs except the short abdomen (tail) is folded up beneath the thorax. Trilobites (now extinct) are named for having three longitudinal lobes.
the thorax
the tympanum
Its exoskeleton.
their eyes
Insects are not composed of minerals. Instead, they are made up of organic materials such as proteins, chitin, and lipids. Minerals are inorganic compounds found in rocks and soil, which are not part of the composition of insects.
It is the tongue.
Insects have three body parts, Head, Thorax and Abdomen. I therefore believe Thorax is the correct answer to your question.
The body part that insects have and cat fleas do not is wings. Fleas are wingless insects that feed on the blood of animals including cats.
The heart is a common part of the body that is found in snakes and insects. Eyes are another common feature between insects and snakes.