1.When a human embryo is developing, the embryo produces a special type of hemoglobin not found in infant, child, or adult blood. Which statement best explains how an embryo can produce a different type of hemoglobin from that of an infant, child, or adult?
A.Humans have genes for different types of hemoglobin, and they are expressed at different times.
B.An embryo and an adult have different genes for hemoglobin.
C.As the embryo develops and cells differentiate, certain genes are lost.
D.Human genes change slowly as a person ages.
2.Which situation would most likely result in evolution?
A.A green parrot has an allele for green feathers and an allele for blue feathers.
B.A butterfly predator sees yellow more easily than it does green, and a population of butterflies includes both phenotypes.
C.A large population continues to grow larger.
D.A single individual dies in a large population.
2007-06-05 05:49:40 · 4 answers · asked by isummerlover 1 in Science & Mathematics ➔ Biology
1) A is the answer but the genes responsible for fetal Hb are repressed in adults.
2) B .....undoubtedly...as the green butterflies arfe less likely to be eaten
well, i am sure about both the answers
2007-06-05 06:19:10 · answer #1 · answered by Mufaddal Kazi 3 · 0⤊ 0⤋
I would say 1a. Different cell types express different genes. As the embryo develops, cells differentiate and some old genes are deactivated, while some new ones become active. Also, gene expression can be regulated by hormones. As the embryo develops, different hormones come into play, triggering certain expression patterns. Genes change and can become lost, but it is rarely in a controlled fashion, more commonly as a result of mutation (which can lead to cancer and other disorders).
2B. The yellow butterflies will be eaten by the predator, since they will be more visible. The green ones will survive, and pass on thier genes, leading to an increased incidence of green butterflies. Eventually, yellow may be phased out entirely.
2007-06-05 14:12:12 · answer #2 · answered by andymanec 7 · 0⤊ 0⤋
Question 1 the answer is (I'm 90% sure) A
Question 2 the answer is B
2007-06-05 13:16:06 · answer #3 · answered by PIFKO 2 · 0⤊ 0⤋
i'm not sure for the answer to no. 1, but the answer to number 2 is B.
2007-06-05 13:10:18 · answer #4 · answered by Anonymous · 0⤊ 0⤋