All animals are heterotrophs as in they can't produce their own energy like plants can which is why they are autotrophs. Herbivores eat plants, carnivores eat animals, and omnivores (humans) eat both.
Answer a)
The students should only have changed one variable to test for germination of seeds. They should have just changed the seed types and rest all factors like temp, pH should be kept constant for all of them.
Answer b)
The procedure could be changed as follows. The students should place three of each types of seeds in the petri dish. They should keep all the conditions like nutrients, temperature, pH constant for all the three dishes. After this observations should be made to check which seed germinates faster.
Answer:
Abraham Lincoln made it illegal .
