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2 years ago

In Figure 33–6, what structure is labeled A? What is the role of the delicate network of

Biology

2 answers:

ryzh [129]2 years ago

7 0

Answer:

The structure labelled as A must be alveoli.

Explanation:

Alveoli or alveolar sac are present in lungs.They are also called as air sacs. The alveoli of lungs provide a large surface area for gaseous exchange. The number of alveoli in human lungs has been estimated to be approx. 300 million. The rich network of capillaries surrounding them help in exchange of gases. Both alveolar wall and capillary wall are made of squamous epithelium. It allows the exchange of gases according to their partial pressure differences.

BabaBlast [244]2 years ago

4 0

Heyo the answers to the multiple choice are A B B A C A C D A C B D D B B C C A D B I'll have the essay questions and fill in the blanks after my test is graded or you can just look them up.

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Consider this segment of a food web: Snails and grasshoppers eat pepper plants; spiders eat grasshoppers; shrews eat snails and

attashe74 [19]

Answer:

the correct option is E.

Explanation:

in this case the shrew occupies the level of both secondary and tertiary consumers.

as the shrew eats spider( a secondary consumer) so it is a tertiary consumer but it also eats snails( a primary consumer) so it is therefore a secondary consumer also.

so the shrew occupies both secondary and tertiary consumer trophic level.

6 0

2 years ago

In beans the pod texture and growth form genes are located on different chromosomes. There are two varieties of beans in a farme

irina1246 [14]

Answer:

a. Genotype in F1 - TtBb

Phenotype in F1 - tough pods, bush-type growth

b. Proportion of F2 that are heterozygous for bush-type growth form = 5/8

c. Proportion of the F2 with tender pods = 1/4

d. Proportion of F2 that are heterozygous for growth form and have tender pods = 1/8

Explanation:

Since the two traits are located on different chromosomes, they will independently assort during gametes formation. T is dominant over t and B is dominant over b.

Two true-breeding varieties were crossed at the beginning of the program:

TTBB x ttbb

All F1 plants will have the genotype TtBb with tough pods and bush-type growth form.

Advancing the cross to F2:

TtBb x TtBb

Progeny

1 TTBB - tough pods, bush-type

2 TTBb - tough pods, bush-type

2 TtBB - tough pods, bush-type

4 TtBb - tough pods, bush-type

1 TTbb - tough pods, climbing-type

2 Ttbb - tough pods, climbing-type

1 ttBB - tender pods, bush-type

2 ttBb - tender pods, bush-type

1 ttbb - tender pods, climbing-type

Proportion of F2 that are heterozygous for bush-type growth form = 10/16 = 5/8

Proportion of the F2 with tender pods = 4/16 = 1/4

Proportion of F2 that are heterozygous for growth form and have tender pods = 2/16 = 1/8

7 0

2 years ago

Approximately 90% of human cancer cells exhibit significant levels of telomerase. Does this mean that telomerase is an oncogene?

alukav5142 [94]

Answer:

No, telomerase is not an oncogene. It prevents the senescence that would occur due to shortened telomeres, but the cell proliferation might still be mitogen-dependent.

Explanation

telomerase is not responsible for causing deregulation while oncogenes cause deregulation .

Telomeres length shorten after the cell division which stops them to divide again and cell die.

Telomerase prevents this decline in some kinds of cells, including stem cells, by lengthening telomeres, and the hope was that activating the enzyme could prevent senescence.

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2 years ago

What is the basis of good nutrition because it is essential to all form of metabolism in the body

satela [25.4K]

The answer is: Water

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2 years ago

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Which is an accurate description of the northern hemisphere at the time of the summer solstice?

Alexus [3.1K]

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2 years ago

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