Answer:
The mother can carry a full-term baby with A blood type because the mother's blood does not mix with the baby's blood, so the mother's immune system does not activate attacking the baby.
Explanation:
The reason why a mother with B blood type and A antibodies in her system can carry a full-term pregnancy is thanks to the placenta. The placenta is a shared organ between the mother and the baby. Its function is to protect the baby and produce the necessary exchanges of nutrients and wastes between the maternal blood and the baby's blood. As the two types of blood are separated, and they never get in contact during pregnancy, the immune system of the mother does not recognize the baby as a treat. The mother can have A antibodies in her plasma due to a previous pregnancy where during delivery, the two types of blood mixed, also it can be due to any contact with the A blood type. When the foreign blood enters the body, the immune system forms antibodies for it.
The four postulates of the natural selection include.
1. individuals possessing particular traits are have higher likelihood of surviving and reproducing.
2. different individuals in a population have different traits
3.reproductive and survival rate vary with individuals in a given population.
4. some trait differences are inheritable.
Both tested the idea of spontaneous generation.
Sponges are similar to other animals in that they are multicellular, heterotrophic, lack cell walls and produce sperm cells. Unlike other animals, they lack true tissues and organs, and have no body symmetry.
The shapes of their bodies are adapted for maximal efficiency of water
flow through the central cavity, where it deposits nutrients, and leaves
through a hole called the osculum. Many sponges have internal skeletons of spongin and/or spicules of calcium carbonate or silicon dioxide. All sponges are sessile
aquatic animals. Although there are freshwater species, the great
majority are marine (salt water) species, ranging from tidal zones to
depths exceeding 8,800 m (5.5 mi).
