A particular cross gives a modified dihybrid ratio of 9:7. What phenotypic ratio would you expect in a testcross of the fully heterozygous F1 crossed with the fully recessive type? Diagram the testcross using A,a,B,b as symbol sets
What will be an ideal response?
1:3 AaBb × aabb > AaBb, Aabb, aaBb, aabb
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Research has shown that cytokinin levels fluctuate seasonally in temperate plants. What season would you expect to see the lowest levels of cytokinins and why would this be adaptive?
A. Spring, because lower levels of cytokinin allow auxin to promote rapid growth in stem height. This will allow the plant to compete effectively for sunlight. B. Summer, because lower levels of cytokinin would slow growth down and delay leaf aging. This will allow the plant to maximize the production of starch and increase it's sugar reserves. This will help ensure the plant's survival through Autumn and Winter. C. Autumn, because lower levels of cytokinin at this time of year will induce the production of ethylene. This will result in maturation of fruit and ensure effective seed dispersal before Winter. D. Winter, because lower levels of cytokinin will place buds into a dormant state. This will protect the underlying tissues from freezing until Spring. Clarify Question · What is the key concept addressed by the question? · What type of thinking is required? · What key words does the question contain and what do they mean? Gather Content · What do you already know about cytokinin levels and seasonality? How does it relate to the question? Consider Possibilities · What other information is related to the question? Which information is most useful? Choose Answer · Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer? Reflect on Process · Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
Currently, the International Union for Conservation of Nature and Natural Resources (IUCN) does not monitor threats to:
a. vertebrates b. plants c. invertebrates d. mammals e. bacteria
What enzymes are used to cut DNA molecules? How do they work?
What will be an ideal response?
Which statement is false?
a. A nerve will not fire unless a stimulus exceeds the threshold. b. An action potential is an all-or-nothing event. c. An action potential continues indefinitely until a quenching signal is released. d. An action potential is self-propagating. e. An action potential transmission depends on activities at the membrane.