Answer: B costal erosion causes the beach to wear away
Answer: True
Explanation:
<u>A cell membrane consists of a lipid bilayer made of polar phosphate head and a nonpolar lipid tail.</u> It is semipermeable and regulates the transport of materials through it. For this,<u> it is selectively permeable</u> and since it is made of lipids, hydrophobic and small polar molecules can diffuse easily through it by simple diffusion and down their concentration gradient. However, polar molecules, large molecules (such as glucose) and ions are not able to pass through it because they are repelled.
To accomplish the transport of these molecules that can not diffuse, proteins embebbed in the membrane function as carriers that enable the transport of polar molecules, large molecules and ions by passive (through facilitated diffusion, down its concentration gradient) or active transport (movement against its concentration gradient).
Answer:
b. Aldosterone promotes sodium reabsorption in the kidneys.
Explanation:
Once it is produced by the adrenal gland it stimulates the mineralocorticoid receptors on the distal tubule and collecting duct of the kidney's nephrons. This causes sodium reabsorption in the kidneys indirectly affecting water retention.
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.
Ecological succession is a process of inhabiting a zoological area by a group of organisms. it involves many stages to reach the climax stage such as primary, secondary, tertiary names basing on the habitat where it occurs. once the organisms reach the most stable stage of the succession. thus it maintains equilibrium
Succession helps restore the equilibrium of an ecosystem by forming up new species, diversifying species, and basically by replacing the damaged, deranged, or disturbed community. For instance, when a sudden climate change occurred in a community, such as drought, dryness, fire, or heat waves, all living things that depends on water or survives in a cool, wet environment will die or migrate somewhere else. Thus, leaving that community vacant and/or unoccupied by any living things. Succession, then, will take place in that area by going through various stages until reaching the climax stage, in which the ecosystem is complete again. c: hope i helped :D
