Hey There!
Here is your answer:
Your answer is that a experiments should be controlled because the experiment could go out of control which could harm or hurt someone.
Also the definition of a controlled experiment is a part of the experiment that's not touched.
Ex: Water is your controlled experiment that's because our not doing anything to the water.
If you need anymore help just ask me!
Hope this helps!
Explanation:
The problem says that the hairless phenotype never breeds true. That means that it's not the result of a homozygous genotype (H₁H₁ or H₂H₂), so it is caused by the heterozygous genotype (H₁H₂).
The <u>expected </u>offspring from the cross between two Mexican hairless would be:
<h3>P
H₁H₂ x
H₁H₂</h3><h3>F1 1/4
H₁H₁, 2/4
H₁H₂ and 1/4
H₂H₂.</h3>
And the <u>expected</u> phenotypic ratio 3:1. However, the observed offspring shows a 2:1 ratio. What's happening?
If the observed phenotypic ratio in the offspring of a monohybrid cross (a single gene with two alleles) is 2:1, we can suspect that one of the genotypes is lethal in homozygosis and therefore does not appear in the progeny (the puppies are born dead).
If we proposed that the H₂ allele is lethal in homozygosis, then:
- The H₁H₁ genotype would cause normal puppies --> 1
- The H₁H₂ genotype would cause hairless puppies --> 2
- The H₂H₂ is lethal and causes the death of puppies --> 0
The phenotypic ratios change to 2:1, as observed in the experiment.
Answer:
Rotifers are specialists at living in habitats where water dries up regularly.
The Monogononta, which have males, produce fertilised 'resting eggs' which can resist desiccation (drought) for long periods.[11]
The Bdelloids, who have no males, contract into an inert form and lose almost all body water, a process known as cryptobiosis. Bdelloids can also survive the dry state for long periods: the longest well-documented dormancy is nine years. After they have dried, they may be revived by adding water. In this, and several other ways, they are a unique group of animals.[12]
Explanation:
The front has a ring of cilia circling the mouth. This gave the rotifers their old name of "wheel animalules". There is a protective lorica round its body, and a foot. Inside the lorica are the usual organs in miniturised form: a brain, an eye-spot, jaws, stomach, kidneys, urinary bladder.
Rotifers have a number of unusual features. Biologists suppose that these peculiarities are adaptations to their small size and the transient (fast changing) nature of its habitats.
An experiment or survey must be controlled in order to receive accurate results.
In an experimental group, the independent variable is changed. But in the control group, the independent variable stays the same.
Answer:
The correct answers are -
A. Find the absolute age of rocks at both locations.
B. Compare a layer at one location to layers at other locations
C. Identify index fossils in one or more layer at one location.
Explanation:
A scientist who studied the earth and different aspects such as it's structure and the materials it made if up known as a geologist. Classifying rocks and discovering various components and matter on earth are the major duties of a geologist.
At some point, rocks can be located at a distance beyond the reach of geologists. Nevertheless, they have a way of studying, and comparing the layers of those rocks helps them to understand the basic difference in the earth locations and the presence of certain components of earth.
Comparing rocks and layers can include these steps at first by geologists-
A. Find the absolute age of rocks at both locations.
B. Compare a layer at one location to layers at other locations
C. Identify index fossils in one or more layer at one location.
