Which region of the frog blastula corresponds to the future dorsal side of the embryo?
A) morula
B) primitive streak
C) archenteron
D) gray crescent
E) blastocoel
Answer: D) gray crescent
You might also like to view...
Of the following molecules, which would not be expected to be moved across a membrane by simple diffusion?
A) oxygen B) fatty acids C) water D) glucose E) dimethylurea
Which structure holds homologous chromosomes tightly together and supports them as they undergo recombination?
a. kinetochore b. centromere
c. microtubules d. spermatozoa e. synaptonemal complex
After mutations begin a cancer, other factors that influence whether the disease proceeds include
A) how old a person is and whether he or she smokes. B) whether a person has had cancer before and its location in the body. C) location of the cancerous cell in the tissue and how specialized the cell is. D) whether or not a person's relatives have cancer.
The significance of one new and one parental strand in each new DNA molecule would be that:
1.New strands are more susceptible to mutation.
2.DNA polymerase will only work on a parental strand.
3.Having an original strand is needed to prevent errors during the replication process.
4.Strands can only pair with existing strands.