The first answer is c and d and the second answer is a
Most terrestrial animals crawl. Snails and slugs crawl on a specialized foot. Newts, salamanders and lizards crawl too. Frogs and toads crawls when they are not hopping and so do insects. Flies, moths and bees crawls when not in flight. Some animals crawls at some stages of life but not others - for example baby humans crawl as do caterpillars before they turn into butterflies!
Hope this helps :)
C
This is because the burning of the two fossil fuels releases carbon dioxide into the atmosphere it does not affect the actual amount of carbon on Earth, which stays constant.