Final answer:
Alveolates exhibit a variety of feeding modes including heterotrophic consumption, photoautotrophy, and parasitism, so the correct answer to the question is that none of these feeding modes are missing from alveolates.
Step-by-step explanation:
The alveolates are a diverse group of protists which include various feeding modes among their members. Within the alveolates, we find species that are heterotrophic consumers, such as certain ciliates and dinoflagellates that engulf prey or absorb nutrients. Some alveolates, like other dinoflagellates, are photoautotrophs and carry out photosynthesis. We also have alveolates that are parasites, like the malaria-causing genus Plasmodium. Given these feeding strategies cover the options provided in the question, we can conclude that none are missing from the list of feeding modes exhibited by the alveolate group.
Protists with the capability to absorb nutrients from dead organisms are referred to as saprobes. This term describes organisms that decompose organic matter.
Organisms described as chemoheterotrophs rely on organic compounds for both energy and carbon source, as opposed to autotrophs which typically utilize inorganic carbon (like carbon dioxide). Chemoheterotrophs can be further categorized based on their oxygen requirements, such as facultative anaerobes which can survive with or without oxygen, or obligate anaerobes which can only live in the absence of oxygen.