Out of the following given choices;
(1) an increase in the number of clams
(2) a decrease in the number of water plants
(3) an increase in the number of crabs
(4) a decrease in the number of crayfish
The answer is D. Crayfish are are freshwater crustaceans resembling small
lobsters. Clams and crabs are found in marine waters. Most crayfish cannot
tolerate polluted water. Crayfish feed on animals and plants, either living or
decomposing, and detritus, therefore a decrease in small invertebrates in the river
would decrease their food source thence
consequently affect their numbers.
Epinephrine triggers a direct signal transduction pathway.
I know this because when epinephrine binds to it's receptor example on a muscle cell,this is known as a type of G protein -coupled receptor,signal transduction cascade is triggered and this involves the production of a second messenger molecule cyclic AMP(cAMP).
Epinephrine also know as Adrenaline or sus-phrine.
It is a vasoconstrictor,broncho dilator and a sympathetic stimulant.
It constricts the peripheral abdominal organs as well as a stimulating the heart beat thereby raising the blood pressure,it also relaxes the spasms of the bronchial muscles thereby promoting ventilation of the lungs.
The answer is <span>B. phagocytosis
</span>
Phagocytosis is a process in which cell ingests large fragments of matter, for example, bacteria. According to the endosymbiotic theory, a host cell ingested symbiotic bacteria (through phagocytosis). Ingested bacteria later specialised into mitochondria or chloroplasts. The evidence for this theory is that mitochondria and chloroplasts similarly to bacteria have their own circular DNA and their own transcriptional and translational machinery.
