In which part of the eye will you locate the rods and cones? a. Pupil b. Iris c.
ID: 163874 • Letter: I
Question
In which part of the eye will you locate the rods and cones? a. Pupil b. Iris c. Retina d. Optic Nerve Most infants will speak their first words by 12 months of age. a. True b. False In ____ syndrome, an individual has an extra 21^st chromosome. a. Down b. Turner's c. d. Fetal Alcohol Which of the following is a description of twins? a. One egg is fertilized by two different sperm b. One egg splits and is then fertilized by two different sperm c. Two eggs are fertilized by two different sperm d. Two eggs are fertilized by the same sperm Which of the following is considered to be the most critical period of prenatal development? a. Germinal Stage b. Embryonic Stage c. Fetal Stage d. Neonatal Stage Which of the following is a reflex that is present at birth? a. Sucking b. Startle c, Rooting d. All of the above reflexes are present at birth At birth, an infant has a highly developed visual system. a. True b. FalseExplanation / Answer
Q.1. Rod and cone cells are seen in retina part of eye. These two types of cells act as photoreceptors. Rod cells are larger in numbers and generally not sensitive to color. The cone cells are less in number than the rod cells and they are color sensitive. So the correct option is (c).
Q.2. Most babies talk their first simple word at the end of 12 months. So the statement is TRUE (a).
Q.3. People who inherit an unbalanced translocation involving chromosome 21 may have extra genetic material from chromosome 21, which causes Downsyndrome. So the correct option is (a)
Q.4. Dizygotic twins or fraternal twins are born when two eggs are independently fertilized by two different sperm cells. The two eggs, or ova, form two zygotes, hence the terms dizygotic has been coined. So the correct option is (c)
Q.5. The most critical period in pre-natal development is the embryonic stage since the various teratogens (external toxic substances such as alcohol, tobacco, radiation etc.) can invade the womb and badly harm the baby in this stage. So the correct option is (b).
Q.6. The correct option is (d). The baby usually shows all the three reflexes (in option a, b and c) at birth.
Q.7. At birth an infant though has all the components of a complete visual system but these are immature. So it takes time to develop. Hence the correct option is FALSE (b)