The Moro reflex is a primitive reflex present in infants. It is triggered by a sudden loss of support or a loud noise, causing the infant to throw their arms out, arch their back, and then bring their arms together in an embracing motion.

The rooting reflex is an innate survival mechanism present in newborns. It helps the infant locate a source of food, such as a mother's breast or a bottle. When the cheek is stroked, the infant automatically turns toward the stimulus and opens their mouth to suck, which is essential for early feeding and nourishment.

The rooting reflex is an innate survival mechanism present in newborns. When the corner of an infant's mouth or cheek is stroked, the baby automatically turns their head toward the stimulus and opens their mouth. This reflex is essential for locating the breast or bottle for feeding, ensuring the infant can successfully latch and receive nutrition.

The Moro reflex is a primitive reflex observed in infants when they are startled or experience a sudden change in position. It involves the infant throwing their arms outward and then bringing them back toward the body, resembling an embrace. This reflex typically emerges shortly after birth and is usually integrated or disappears by the age of four to six months as the nervous system matures.

Studies in developmental psychology, such as those using preferential looking techniques, consistently show that infants are biologically predisposed to attend to human faces. This preference is thought to be an evolutionary adaptation that promotes social bonding and survival. Even at a very young age, infants track and focus on face-like patterns more readily than on other complex visual stimuli, highlighting the importance of social interaction in early development.

The Babinski reflex is a primitive reflex observed in infants. When the sole of the foot is firmly stroked, the big toe typically moves upward or toward the top surface of the foot, while the other toes fan out. This reflex is a standard indicator of neurological development and typically disappears as the nervous system matures.

Infants are born with a set of innate, involuntary responses known as primitive reflexes, such as the rooting, sucking, and grasping reflexes. These reflexes are essential for survival, helping the newborn feed and protect themselves during the early stages of life. As the infant's nervous system matures, these reflexes are gradually replaced by voluntary, purposeful movements, marking a key milestone in human development.

The grasping, rooting, and sucking reflexes in infants are automatic, involuntary responses that facilitate survival and early interaction with the environment. These are classified as adaptive reflexes because they provide the infant with essential tools for feeding and physical security during the vulnerable neonatal period.

Human development involves both quantitative and qualitative changes. Quantitative changes refer to measurable increases in size, such as height or weight. Qualitative changes refer to shifts in the nature, structure, or organization of functioning, such as the development of abstract reasoning or complex emotional regulation, both of which are essential for maturation.

Primary sex characteristics are directly involved in reproduction, such as ovaries in females and testes in males. Secondary sex characteristics are physical features that emerge during puberty but are not directly involved in reproduction, such as the deepening of the male voice, breast development, or changes in body hair distribution. Option D correctly identifies an example of each category.