Insects have exoskeletons. They do not have bones on the inside.
No. Placental means a type of mammal, and mammals are vertebrates, meaning they have a backbone and an entire internal skeletal structure. Insects do not have a backbone, and are therefore invertebrates.
No. All mantids including praying mantises are insects. They are invertibrates as their skeletal system is external. This type of bone structure is called an extoskeleton. Reptiles have internal bones and a similar skeletal system to humans.
An endoskeleton is an internal skeleton found within the body of an organism, providing support and structure. In contrast, an exoskeleton is an external skeleton that covers the body, serving as protection and support for the organism. Humans have an endoskeleton, while insects typically have an exoskeleton.
Very much a vertebrate! It is a mammal, and all mammals are vertebrates- invertebrates are all animals that have no internal skeletal structure, but have either gained an exoskeleton (such as insects) or have no skeletal structure at all (i.e. jellyfish, etc.)
Zero
Yes. Flatworms lack a skeletal structure, and any creature without a skeletal structure is classified as an invertebrate.
bone
The structure of a leaf is skeletal
No. As egg-layers with six legs and no internal skeletal structure, they are pretty thoroughly insects. More specifically, the fact that they have wings covered with an external carapace makes them excellent candidates to be beetles.
the hands contains pairs of opposing skeletal muscles
gives the frame /structure
No. They are not invertebrates because they have a skeletal structure