. I think that bivalves have evolved to have smaller head regions because they have also evolved to have bigger shells or valves than cephalopod
Answer: a hypothesis.
A hypothesis means a theory or a guessed explanation made, based on limited evidence as a starting point for further investigation.
Any characteristic, whether a physical trait, a behaviour, a physiological adaptation etc can make an organism more or less likely to survive in a particular environment.
A dark colour could help a rabbit survive if it lives in a dark forest, because predators can't see it so well, but it would be less likely to survive in the arctic, where the environment is all white and it would show up.
In terms of the characteristics, think about: does it help the organism get food? Does it help protect the organism from predators? If it does, that organism is more likely to survive, and pass the characteristic on to it's offspring. If a bacterium has a characteristic of not being killed by antibiotics, this will help it to survive and breed.
There are tons of answers you could have.
One, for example:
Increased levels of CO2 decreases DO levels in the water and suffocates organisms, leading to population drops that can cause a genetic bottle neck effect, thus decreasing overall biodiversity. This could lead to extinction
Answer:
The envelope is an outer lipid bilayer that is studded with proteins. The function of the envelope is to identify and bind some receptor sites on the host membranes. After fusing with the cell membrane, it allows to capsid and genetic material to enter the cell and infect it.
Explanation:
