Embryonic development begins with a single egg fertilized by a single sperm, forming a zygote which then divides by
mitosis. How many cells are present in the embryo at the conclusion of four mitotic divisions?
a. 2
b. 4
c. 8
d. 16
e. 32
ANSWER: d
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Dynamic instability is the rapid growth and shrinkage of:
A. microfilaments. B. intermediate filaments. C. microtubules. D. Answers a and c are correct.
The first person acknowledged to have seen living,
moving cells by using a microscope was a. Robert Hooke. b. Robert Brown. c. Galileo Galilee. d. Rudolf Virchow. e. Anton van Leeuwenhoek.
If you add 2g of sugar to water,what do you think is happening to the water potential?
(a) nothing (b) It will stay at zero (c) It will become more negative (d) It will become more positive (e) Two of the above
One day after a biology class four of your friends argue about the difference between phylogeny and systematics. Which friend is right?
A. Friend A states that systematics and phylogenies are really the same, one is more recent than the other, but basically they are the same. B. Friend B says that systematics is the same as cladistics and cladistics is reconstructing clades, which ultimately lead to the development of phylogenies. C. Friend C argues that systematics is the actual collecting and cataloguing of specimens into museums that can be used later by scientists to construct clades and phylogenies. D. Friend D says that the way she remembers is that systematics is the reconstruction and study of phylogenies.