Consider the following statements about viruses: 1. The tobacco mosaic virus was the first virus discovered. 2. Viruses can have a protein coat called capsid. 3. Viruses can reproduce outside host cells. Which of the above is/are correct? MCQ with Answer and Explanation

Explanation:
Erythroblastosis fetalis (hemolytic disease of the newborn) is primarily caused by Rh incompatibility. It occurs when an Rh-negative mother carries an Rh-positive fetus. During the first pregnancy, fetal Rh+ red blood cells may enter the mother's circulation, prompting her to produce anti-Rh antibodies. In subsequent pregnancies with an Rh+ fetus, these antibodies cross the placenta and destroy the fetal red blood cells, causing severe anemia and jaundice.

Explanation:
The Bohr effect describes how an increase in pCO2 or a decrease in pH (increase in H+) reduces hemoglobin's affinity for oxygen, shifting the oxygen dissociation curve to the right and promoting oxygen unloading. Conversely, in the lungs, where pCO2 is low and pH is relatively higher (more alkaline), the Bohr effect works in reverse: hemoglobin's affinity for oxygen increases, facilitating the loading (binding) of oxygen to hemoglobin. The Haldane effect describes the reciprocal relationship for CO2 transport.

Explanation:
The Reticular Activating System (RAS), or Ascending Reticular Activating System (ARAS), is a complex network of neurons located in the core of the brainstem (spanning the medulla, pons, and midbrain). It projects diffusely to the thalamus and cerebral cortex. Its primary function is to regulate the overall level of arousal, consciousness, and wakefulness of the brain. It filters incoming sensory information, allowing important stimuli to reach conscious awareness, and plays a crucial role in the sleep-wake cycle and transitions between sleep stages.