Answer:
Gastrulation takes place after cleavage and the formation of the blastula and the primitive streak. It is followed by organogenesis, when individual organs develop within the newly-formed germ layers. Each layer gives rise to specific tissues and organs in the developing embryo.Cells in each germ layer differentiate into tissues and embryonic organs. The ectoderm gives rise to the nervous system and the epidermis, among other tissues. The mesoderm gives rise to the muscle cells and connective tissue in the body. The endoderm gives rise to the gut and many internal organs.
Answer:
Molecular evidence
Explanation:
Earlier archaea were considered as bacteria because they show some similarities with bacteria like binary fission as mode of reproduction, lack of a nucleus, etc.
Later Carl Woese separated bacteria in a different domain and divide prokaryote into two domains called bacteria and archaea. He separated archaea from bacteria on molecules evidence.
He compaired rRNA sequence between bacteria and archaea and observed that they both differ in rRNA sequence which allowed him to make a separate domain for archaea.
There are several specific characteristics for procaryote and eucaryote:
- Procaryotes has a cell wall, in addition to the cell membrane.
- procaryotes has chromatin in the cytoplasm, they do not have a nucleus.
- Procaryotes are small cells visible only at the microscope with x100 objective.
About the eucaryotic cells:
- Eucaryotes have mitochondria,
- Eucaryotes have endoplasmic reticulum
- Eucaryotes have a nucleus with DNA chromatin and nucleoli inside it.
- Eucaryotes are visible in the microscope x40
Answer:This is the exact answer so you might want to re-word it.
All the organisms an image one have a similar skeletal structure, with two legs, two arms, ribs, vertebrae, and similarly shaped skulls. However, the sizes and shapes these structures very among the species. For example, the hands of the chimpanzee, Gorilla, and orangutan are proportionally larger than the hands of the human but smaller than the hands of the gibbon.
