Answer:
The correct answer is option 3. a nucleus.
Explanation:
The first genetic material present in the early organisms were RNA which was present in the microscopic organisms back then 3.5 billion years ago which means it is normal to have RNA in such microfossils chemical analysis.
Since, the nucleus was not present in early life forms of prokaryotes like bacteria. so, it is unusual to find nucleus in the fossils of stromatolite rocks.
Thus, option III is the correct answer.
Answer:
Amoebalike protists, flagellates, ciliates, and spore-forming protists.
Explanation:
Protists are eukaryotes, which means their cells have a nucleus and other membrane-bound organelles. Most, but not all, protists are single-celled. Other than these features, they have very little in common. You can think about protists as all eukaryotic organisms that are neither animals, nor plants, nor fungi.
Hope this helps
Hermit crabs and giant tritons have a commensalism type of relationship.
Answer:
Earthworm - have a coelom and a closed circulatory system.
Scallops or clams - has a mantle and an open circulatory system.
Starfish - has an endoskeleton made of calcium-rich plates.
Spider - exhibits the phenomenon of molting.
Explanation:
Earthworm belongs to Phylum Annelida. They are metamerically segmented, triploblastic and bilaterally symmetrical. They have a closed circulatory system and a coelom (true body cavity).
Scallops or clams belong to Phylum Mollusca, the second largest animal phylum. They are coelomate, triploblastic, bilaterally symmetrical organisms having an open circulatory system. They have a calcareous shell covered body with a distinct head, muscular foot, visceral hump and a mantle (soft and spongy layer of skin) over the hump.
Starfish belongs to Phylum Echinodermata, which consists of exclusively free-living marine organisms. They have an endoskeleton made up of calcium carbonate structures. They are coelomate, triploblastic and have a water vascular system that is used for respiration, locomotion, food capture and transport.
Spiders belong to Phylum Arthropoda. They have chitinous covered segmented bodies, jointed legs and exoskeletons (hard external shells). Arthropods periodically shed their exoskeletons or shells in order to grow, this process is called molting. They are coelomate, triploblastic, bilaterally symmetrical organisms having an open circulatory system.
