Heartworms can infest the hearts of animals like cats and dogs. The worms get nutrients from the animal, while the animal will die from the infestation. This is an example of

mutualism
commensalism
parasitism

where is the diagram?

if you insert the diagram ill be able to you

a tetrad is the foursome during meiosis made by two homologous chromosomes that have each already replicated into a pair of sister chromatids.

the answer is d.) homologous; have mammary glands