The correct answer is letter A. Venom glands and varied diets are the reasons why cane toads are considered as invasive species in Australia. They cause major ecological imbalance within their immediate surroundings and have caused an infestation all over Australia.
If this is for the scientific process unit, the answer is passing laws to prevent certain types of scientific research. I know because I had this question in biology.
First, he should measure how long it takes for the liquid to become clear if X and Y are mixed together. Then, he should measure how long it takes if he also adds substance A to X and Y. He will find out if substance A is a catalyst. hope this helps :)
B. some substances must be dissolved in water before they can be used
