Just like in humans, radioactive material can damage plant tissues as well as inhibit growth. mutations are possible due to damage caused to the DNA. radioactive material in soil can prevent nutrient from being taken in by plants, causing it to be infertile.
question one is actually mass, and question 2 is D.
By definition, an arthropod is an animal that is invertebrate and has an exoskeleton also known as an external skeleton. In addition they have a jointed appendages. Other characteristics include segmented bodies, open circulatory systems and bilateral symmetry. Based on this we can say that from the list given we can select "endoskeleton" "jointed appendages"
You need to do speed divided by time