Alife cycle in which organisms switch back and forth between diploid and haploid stages
a. is a haploids life cycle
b. is a diploids life cycle
c. is an alternation of generations life cycle.
d. does not exist

one characteristic that is shared by all is a soft body. many

of these invertebrate animals also have an outer shell to protect their

body. oysters, clams, snails, and mussels are all mollusks. so are octopuses, squids, and slugs. mollusks live on land and in freshwater.

after receiving a stimus, the sensory receptors send(s) signals to the appropriate area of the body.  

the must be sensory neurons.  

hope its .