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What are three functions of a starfish's water vascular system?

olchik [2.2K]

The water vascular system of a sea star enables movement, digestion and respiration through the use of water to exert force on limbs known as tube feet. The vascular system is primarily water but also contains coelomocytes, protein and potassium salts.

6 0

3 years ago

22. A plant geneticist is investigating the inheritance of genes for bitter taste (Su) and explosive rind (e) in watermelon (Cit

mylen [45]

Answer:

See the answer below

Explanation:

Using the formula for calculating Chi square ( $X^2$ ):

$X^2$ = $\frac{(O - E)^2}{E}$ where O = observed frequency and E = expected frequency.

The observed frequencies for the four phenotypes are 88, 62, 62, and 81 respectively.

For the expected frequency, the phenotypes are supposed to assort in 9:3:3:1 according to Mendel ratio.

Hence, expected frequencies are calculated as:

phenotype (1) = 9/16 x 293 = 164.81

phenotype (2) = 3/16 x 293 = 54.94

phenotype (3) = 3/16 x 293 = 54.94

phenotype (4) = 1/16 x 293 = 18.31

The $X^2$ is calculated thus:

Phenotype O E $X^2$

1 88 164.81 $\frac{(88 - 164.81)^2}{164.81}$ = 35.80

2 62 54.94 $\frac{(62 - 54.94)^2}{54.94}$ = 0.91

3 62 54.94 $\frac{(62 - 54.94)^2}{54.94}$ = 0.91

4 81 18.31 $\frac{(81 - 18.31)^2}{18.31}$ = 214.64

Total $X^2$ = 35.80 + 0.91 + 0.91 + 214.64 = 252.26

To the nearest tenth = 252

Degree of freedom = n - 1 = 4- 1 = 3

$X^2$ tabulated = 7.815

<em>The calculated </em> $X^2$ <em> exceeds the critical value, hence, the null hypothesis is rejected. The two genes did not assort independently. </em>

4 0

3 years ago

What is the mechanism of natural selection?

borishaifa [10]

The answer is D. The natural selection is a theory which illustrates the gradual process of evolution in the population due to the change of environment. The key point is the mutation (variation) exists in the population before the environment changing. For C, if the environment does not change, though the adaptation is useful to environment, it will not be selected. Because the organisms without the adaptation will not die.

8 0

3 years ago

Select all of the following statements that represent examples of predation. Check All That Apply Deer eat the leaves of a tree.

Fantom [35]

Answer:

A snail eats a clam.

Explanation:

Interactions always occur between organisms in an ecosystem. An interaction between two organisms is called SYMBIOSIS. Symbiosis consists other types which includes PREDATION. Predation is a kind of symbiotic relationship between two organisms in which one kills and feeds on the other in order to obtain energy. The organism that kills is called the PREDATOR while the organism that is killed is called PREY.

In this example, a snail feeding on a clam best represents the example because the snail (PREDATOR) is obtaining energy by killing the clam (PREY). In other options, no organism is killed.

6 0

3 years ago

Use the drop-down menus to match each phrase below with the type of microscope it describes.

VikaD [51]

A compound light microscope magnifies objects in steps.
An electron microscope is the type that was used to observe the first strands of DNA.
A compound light microscope contains a series of lenses.
A compound light microscope includes magnifying glasses.
An electron microscope creates a digital image.
A simple light microscope uses one lens for magnification.

4 0

4 years ago

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