(A) nerve cords, because adults lack a notochord (a dorsal hollow nerve cord).
The most important difference between primary and secondary
groups is that, primary groups are being referred to a family in which every
person has while the secondary group is being referred to the society or the
sociology class in which every person partakes to.This group has to do with the relationships that exist
amongst them.
ecosystem, Biome, biosphere, idk where habitat goes sorry
Answer:
Viruses and Bacteria
Explanation:
Bacteria are single-celled, prokaryotic microorganisms that exist in abundance in both living hosts and in all areas of the planet. By their nature, they can be either "good" or "bad" for the health of plants, humans, and other animals that come into contact with them. A virus is acellular (has no cell structure) and requires a living host to survive; it causes illness in its host, which causes an immune response. Bacteria are alive, while scientists are not yet sure if viruses are living or nonliving; in general, they are considered to be nonliving.
Infections caused by harmful bacteria can almost always be cured with antibiotics. While some viruses can be vaccinated against, most, such as HIV and the viruses which cause the common cold, are incurable, even if their symptoms can be treated, meaning the living host must have a strong enough immune system to survive the infection.
I think the more features two organisms share or the shared anatomical features, the closely related they are. For example; the class insecta (e.g bee, butterfly) and the class arachnida (e.g spider and tick) belong to phylum arthropoda because they have similar anatomical features such as appendages, segmented body among other features.
