Answer:
Arthropods invaded land about 100 million years before vertebrates. This fact most clearly implies that a. arthropods have had more time to co-evolve with land plants than have vertebrates
Explanation:
Arthropods are invertebrates animals. Its evolutionary ancestry dates back to the Cambrian period and they have had more time to co-evolve with land plants than have vertebrates. The vertebrates share a common ancestor. Scientists believe that the last common ancestor of all arthropods is a modular organism with each module covered by its own sclerite.
Scientists will look for evidence like similar body or skeleton structures, internal similarities or maybe sometimes the whole heirarchy to confirm that two speices are closely related to each other.
For example ; in birds, scientists will look for type of feathers, body structure, beaks to confirm the similarity of two birds.
The type of organisms that take energy by eating up other organisms in an ecosystem are called 'CONSUMERS'. Now these consumers are further divided into three major classes:
1. Primary consumers: this type of consumers feed directly from the producers (plants) and they only eat grass, leaves, vegetables, etc. Such animals are also called herbivores. Example: rabbit
2. Secondary consumers: these are the animals that eat up primary consumers (animals that feed only on plants). These animals are called carnivores. Example: snake
3. Tertiary consumers: animals that eat carnivores which eats a herbivore are called tertiary consumers. They can be completely carnivore or omnivore (who feed on animals and plants both). Example: humans (they feed on animals and plants both)
Answer:
The periosteum is one source of precursor cells which develop into chondroblasts and osteoblasts that are essential to the healing of bone. Other sources of precursor cells are the bone marrow (when present), endosteum, small blood vessels, and fibroblasts.
