Maintaining a certain calcium concentration is important for the proper functioning of which cells? Check all that apply.

Which of the following is an important function of child-directed speech? (a) it captures the infant’s attention and maintains communication. (b) it reduces the occurrence of infantile amnesia for the earliest memories of infancy. (c) it reduces the need for reciprocal interaction between caregivers and children. (d) it assists in prolonging rem sleep in infants.

Which of the following is a nonspecific defense against pathogens? - b cells - antibodies - t-cells - inflammation

The heart and lung are located in which cavity ? thoracic