Primary succession is where lichens move into an area with no soil. They will then create soil and make an ecosystem.
1. Expose the bare rock do to volcanic eruption or glacier. The first step to primary succession is to have a place with bare rock, no soil at all. If there is already soil in place, this would be secondary succession.
2. Pioneer species arrives (like lichen). Lichens basically create soil from rock, they are needed to start an ecosystem.
3. Soil start forming and mosses begin growing
. Now the lichens will begin to create a lot of soil, capable of holding life like moss. There still won't be enough nutrients in the soil for anything more complex at this point.
4. Small plants start to grow. Since the moss is starting to die, it will add nutrients to the soil. After awhile, enough nutrients will be in the soil for small plants to grow.
5. Evergreen trees start growing. Evergreen trees are softwood, which will come before hardwood trees during primary succession.
6. Deciduous trees move in. Deciduous trees, like oaks and maples, are hardwood trees and will come last in primary succession. This is the ideal climax community.
Answer:
The options:
A. incomplete digestive tract
B. gastrovascular cavity
C. complete digestive tract
D. complete digestive tract and a gastrovascular cavity
E. incomplete digestive tract and a gastrovascular cavity
The CORRECT ANSWER IS E.
E. incomplete digestive tract and a gastrovascular cavity
Explanation:
Phylum Cnidaria; Cnidarians are diploblastic with two embryonic germ layers -the ectoderm and the endoderm) with well structured tissue, performs extracellular digestion, and use cnidocytes for defence and to catch prey.
Cnidarians have two unique morphological body plans which are referred to as polyp, its sessile in adults, and medusa are mobile; some species has both body structures in their lifecycle.
It undergo extracellular digestion, where enzymes dissolve the food substances as its cells lining the gastrovascular cavity take in the nutrients.
Cnidarians are known to have a body arrangement of incomplete digestive system with just one opening; the gastrovascular cavity that functions as both a mouth and an anus.
The cnidarians undergo extracellular digestion, the food is moved to the gastrovascular cavity, enzymes are present in the cavity, with the cells lining the cavity taken in nutrients. The gastrovascular cavity possess a singular opening that acts as a mouth and an anus; this is referred to as an incomplete digestive system.
The two main tissues are bone and cartilage.
Bone is made up of collagen and calcium phosphate provides support and protection for body organs
Cartilage which is made up of closely packed collagenous fibers provides flexible support for structure such as ear, nose and trachea