Most cnidaria possess a skeletal system known as a exoskeleton, endoskeleton, tibia system, hydroskeleton?

Exoskeleton

1. Hard part that lies outside of the body

2. Develops from ectoderm

3. Composed mainly of  hard non-living material called chitin.

Endoskeleton

1. Hard part that lies inside the body

2. Develops from endoderm

3. Composed of living material i.e. bone tissue

then that particular organisms become extinct.

a

explanation:

many plants naturally reproduce this way, but it can also be induced artificially. horticulturalists have developed asexual propagation techniques that use vegetative plant parts to replicate plants. success rates and difficulty of propagation vary greatly. monocotyledons typically lack a vascular cambium and therefore are harder to propagate.