<span>Explanation: Oxygen is the more electro-negative of the atoms in the water molecule, so it tends to pull the 'shared' electron more to itself. Thus, the oxygen atom has a greater time-share of all electrons, and therefore the hydrogen atoms are more positive for a partial lack of electrons</span>
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Answer: D. The succession of community is completed.
Explanation:
A succession can be define as a series of gradual changes that occur in the biotic community of the ecosystem with respect to the changes that occur in the abiotic or non-living factors with respect to time until the ecosystem attains stability.
A climax community is the community that develops in the end of the ecological succession. It is the stable community which does not require any further change to occur. With the development of the climax community the succession completes.
Multidisciplinarity draws on knowledge from different disciplines but stays within their boundaries. Interdisciplinarity analyzes, synthesizes and harmonizes links between disciplines into a coordinated and coherent whole.
Answer:
a. + glucose, + lactose = On
b. - glucose, - lactose = Off
c. + glucose, - lactose = Off
d. - glucose, + lactose = On
Explanation:
Lac operon has both types of control, repressible and inducible.
Whenever glucose level is low in the cell, an enzyme known as adenylyl cyclase raises the level of cAMP which forms a dimer with CRP protein and they both act as activator of lac operon and cause expression.
Apart from this, when lactose is present in the cell, β-galactosidase enzyme metabolizes lactose to form allolactose which causes allosteric repulsion in the lac repressor and causes its removal from the operator. As soon as repressor is removed lac operon gets activated.
In wild type lac operons, the expression of lac operon occurs when glucose level is low in the cell and lactose is present but in this mutant presence or absence of glucose will not make a difference because CRP will bind Plac promoter independent of cAMP level i.e. activator CRP will work even in high glucose concentration. If lactose is present then lac operon will always express so in option 'a & d' lac operon will express but in option 'b & c' it will not express.
