Answer:
Gastrula
Explanation:
A hollow shaped embryonic structure formed after two weeks of fertilization with three layers is known as gastrula.
The gastrula is formed from the repeated division of the single-layered structured called blastula which later forms three layers called ectoderm, endoderm and mesoderm.
These layers during the process of gastrulation from different organs of the multicellular organisms like the endoderm forms the liver, the ectoderm form the nervous system, the skeletal bone and many others.
Since gastrula structure contains three dermal layers therefore gastrula is the correct answer.
A little trick i learnt: The atomic number reflects how many electrons there are, and there must be an equal charge. therefore, there are the same amount of protons as there are electrons. so if it has 81 protons, we look for number 81 in the periodic table, Thallium
Answer:
What sends oxygenated blood back to the heart from the lungs?
Oxygen-rich blood flows from the lungs back into the left atrium (LA), or the left upper chamber of the heart, through four pulmonary veins. Oxygen-rich blood then flows through the mitral valve (MV) into the left ventricle (LV), or the left lower chamber.
Explanation:
The population must be infinitely large!
Hope this helps!
