Answer:
Variation can be acted on by natural selection.
Explanation:
Variation are the difference that exist in the organism in terms of the body size and can be acted upon by natural selection.
Natural selection could act on the owl body size, favor the selection of owl with small body size especially when resources available are limited and can only sustain small number of individuals leading to availability of owl with small body size in such area and a gradual reduction in the number of owl with large body size.
<span>The gene sequence containing an operator, promoter and repressor is known as an operon. These genes are called as structural genes. the operon is regulated by the presence/absence of the inducer such as glucose/lactose. It may also be a constitutive operon, which works all the time.</span>
Answer:
Both parents have white fur. <em>The only</em> way that this can happen is if their genotypes are both <em>homozygous (bb)</em>. Therefore, both parents pass the (b) allele to every offspring. When you combine two of these alleles, the resulting genotype is <em>(bb);</em> therefore, the resulting offspring have white fur.
Explanation:
A homozygous trait can be described as a trait in which both the alleles for a gene are similar. A heterozygous trait can be described as a trait in which both the alleles of a gene are different. If an allele masks the effect of another allele, it is said to be dominant. the allele that gets suppressed is termed as recessive.
Hence, for a recessive trait to occur both the alleles of a gene should be homozygous recessive.
The punnet square for the above cross is shown below:
b b
b bb bb
b bb bb
Answer:Major functions of connective tissue include: 1) binding and supporting, 2) protecting, 3) insulating, 4) storing reserve fuel, and 5) transporting substances within the body. Connective tissues can have various levels of vascularity. Cartilage is avascular, while dense connective tissue is poorly vascularized.
Explanation:
The laboratories have initiated Phase 1 clinical trials for the use of human pluripotent embryonic stem cells to treat paralyzed patients following spinal cord injury. The first step is to estimate the risks and tolerance of cell transplantation in a man. The fate of stem cells (multipotent or pluripotent) in the body is still poorly understood, and it is not excluded that uncontrolled cell multiplications occur, leading to the appearance of teratomas (tumor developed from pluripotent cells).
Advantages are:
* The safety of the cells also seems to be proven (in short term)
* Rats transplanted seven days after the injury had benefited from reactivation of myelinization of neurons by oligodendrocytes, attenuation of motor neuron loss and improvement of limb motor function.
The disadvantages are:
* Constraints of the ethical and religious order, it is necessary the consent and the approval of the donor and the recipient for the transplant to take place.
* The development of the technique is still new, there is a chance that side effects of the transplant appear years after the operation.
