Answer:
a.) freshwater plants may be rooted here--- Shore
b.) littoral zone--- it is the region of a lake or pond that is nearest to the shore
c.) limnetic zone--- A region of open water in lakes and ponds.
d.) alternately dry and submerged--- Intertidal Zone
e.) extends to edge of the continental shelf--- Neretic Zone
f.) generally low nutrient levels
g.) light penetrates here--- Photic Zone
h.) no photosynthesis occurs here--- Aphotic Zone
i.) benthic zone--- this is purely known as the bottom of the lakes or oceans
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.
The answer it’s Compression
