The answer is A) An inner skeleton made of bone or cartilage. Vertebrates have a column of bones that supports the body and protects the spinal cord, while invertebrates are animals that either have a soft body or a hard outer casing covering their body.
The first one is nucleus, last one is DNA
i tried my best sorry
They Have Different Temperatures during the seasons because of the earths tilt on the axis towards the sun. When The Northern Hemisphere of the earth Is tilted towards the sun, it warms it up, but if its tilted back it will be cold, same for the south!