Answer:
Endocardium
Explanation:
The endocardium makes the innermost lining of the wall of the heart. It is present over the thin layer of connective tissue. The function of the endocardium is to provide a smooth lining for the chambers of the heart. The valves present in the heart also have endocardium. The dense connective tissue of the heart valves is covered by endocardium.
The presence of the smooth endocardium made up of endothelium reduces the surface friction as blood passes through the heart. The endocardium of heart chambers is continuous with the endothelial lining of the large blood vessels that are attached to the heart.
Thymine and cytosine are classified as "Pyrimidines" and have one ring of carbon and nitrogen atoms for each base.
Answer: b. Webbed-toed mice survived better and reproduced more than mice without webbed toes.
Explanation:
Natural selection is a phenomenon that suggests that organisms that have a better structural and morphological advantage over the others have better chances of survival over the others.
The webbed toed mice have a survival advantage over the without the webbed toes because this can help the webbed toed mice to swim. The webbed toed trait will be beneficial and passed on to the next generation of the mice and the webbed toed mice will reproduce more than the mice without webbed toes.
Answer:
The inhibitory transmitter activates ligand-gated potassium channels
Explanation:
When a cell is in hyperpolarized state,the potassium gated channels are taken longer time to close up, Therefore, more K+ leaks out of the axoplasm to the exterior.Therefore the cell appears to continue in the resting state, with more negative value of the cell potential of (-120 mV) and this called hyperpolarization.
However, with the addition of inhibitory transmitter,the ligand-gated potassium channels are activated,Theses channels closes up.Then sodium gated channels, which were initially in refractive state reopens, sodium ions diffuses inwards for depolarization, and the neuron returns to depolarized state.
Answer:
(2) exchange food, oxygen, and waste between
mother and fetus
Explanation:
In most mammals like humans, the fetus produced as a result of the fertilization of the sperm and egg, develops in the uterus or womb of the female. However, this developing fetus cannot yet fend for what it requires for survival and is still dependent on the mother e.g nutrients, oxygen etc. How do this substances get to the fetus? Here comes the role of the PLACENTA.
Placenta is an organ in the uterus that serves as a connection between the mother and the fetus in her womb. The placenta enables the mother to pass digested nutrients to the fetus and exchange gases (oxygen and Carbondioxide) between them via the umbilical cord. The placenta also enables the mother remove waste produced by the fetus into her bloodstream.
