The placenta is the temporary association of fetus and maternal tissue. It is meant for nutrition and transport of different substances.
Explanation:
The placenta is a temporary association of fetal and maternal tissues. The placenta is formed from the trophoblast of the blastula. These trophoblasts form chorionic villi which later forms the placenta. The chorion and allantois also take part in the formation of the placenta. Hence, the human placenta is known as the chorioallantoic placenta. The process of formation of the placenta is known as placentation.
The placenta has several functions but the major function is to provide nutrition to the fetus. The developing fetus gets nutrition from the mother's body by the placenta. The placenta provided with blood vessels which help in the transportation of different substances. It also helps in gas exchange between the mother and baby. Thus it plays a vital role in fetal respiration. The metabolic wastes diffuse through the placenta. Placenta also stores fat, glycogen, which participates in protein metabolism.
When a mustard plant seedling is transferred to an environment with higher levels of carbon dioxide, the new leaves have a lower stomata-to-surface-area ratio, it is because the concentration of carbondioxide is high in the surrounding so the plant produce small leaves having less number of stomata. If the concentration of carbondioxide is lower so big leaves are produced having maximum number of stomata.
