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Tom [10]
3 years ago
7

Do you think that all pollen germinates indiscriminately on all stigmas?

Biology
1 answer:
r-ruslan [8.4K]3 years ago
4 0
Pollen tube growth is one of the most fascinating—and essential—phenomena in the life cycle of flowering plants. After a compatible interaction between pollen grains and the stigma surface, the pollen germinates and forms the pollen tube, which grows through the stigma, style, and transmitting tract to deliver the sperm cells to the ovule." 
2) Although pollens of many species germinate in simple aqueous media, stigmas do not provide satisfactory sites for the germination of most foreign pollen... Stigmas not only provide the proper conditions for the germination of pollen from their particular species, they actively inhibit the germination of pollen of many unrelated species.
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According to the text physical exercise in late adulthood encourages the birth of new neurons in areas responsible for learning
Sindrei [870]
The answer is <span>neurogenesis and hippocampus</span>
7 0
3 years ago
Using the graphs below, determine which water drop rate leads to the highest seed growth.
expeople1 [14]

Answer:

C. 50 drops/hr

Explanation:

As we can see in the description of the graph above, 50 drops/hr was the rate of water fall that was most successful in plant growth. This is because with this rate, the seeds germinated more quickly, the seedlings showed a strong and fast vegetative growth, besides that at the end of 5 days, it was observed that germination of almost 100% of the seeds occurred. These facts cannot be observed with the other waterfall rates, so the correct answer is 50 drops/hr.

6 0
3 years ago
A phenotypic ratio for a dihybrid cross is predicted to be 9:3:3:1. The experimental values are:
Maslowich
Two traits that we are examining are the color (purple/white) and the smoothness. 
In our sample, we have 135 individuals ( 75 +28+24+8= 135).

Since we know that expected ratio of a dihybrid cross, is <span>9:3:3:1 we can calculate what is the expected values of each phenotype is.

So, for the white wrinkled phenotype, we expect that there will be one-sixteenth of the whole sample ( there are 16 parts of the whole sample 9+3+3+1=16).
So, we multiply the whole sample- 135 with one-sixteenth (or </span>0.0625) and get 8,4375.
When you calculate the values for all phenotypes you get results shown in the attached excel table.
When you have your expected and experimental values you compare them with a chi-square test. (The test determines if the difference between the expected and experimental results is statistically significant).


4 0
3 years ago
Read 2 more answers
Why doesnt pepsin, the enzyme released in the stomach to
Fiesta28 [93]

Answer: unfavourable ph condition for the pepsin

Explanation: during digestion, enzymes are needed to aid the process.digestive enzymes are biological catalyst that breakdown large food particles into digestible form .

As biological catalyst, enzymes require an optimum temperature and pH condition.outside this temperature or pH,the enzyme is denatured.

In the stomach, hydrochloric acid is required to convert pepsinogen into it's active form,pepsin.the acid also creates an optimum low pH that pepsin needs to function.

As the food moves to the small intestine,the pH is alkaline and is unfavourable for pepsin to function.

4 0
3 years ago
In which phase does a cell spend most of its time?
Mnenie [13.5K]

Answer:

a

Explanation:

4 0
3 years ago
Read 2 more answers
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