Question

1. Chum salmon (Oncorhynchus keta) are born in freshwater environments and then migrate to the sea. Near the end of their lives, they return to the freshwater stream where they were born to spawn. In freshwater, water constantly diffuses into the body and ions are lost from the body. In salt water, body water diffuses out of the body and excess ions are gained from the water. A salmon's gills have special cells to pump salt in or out of the body to maintain homeostasis. In response to the salmon's moves between freshwater and salt water, some cells in the gills are produced and others are destroyed. These changes made in the cells of the gills during the lifetime of an individual salmon are an example of which of the following

   	a.	evolution
   	b.	trade-offs
   	c.	acclimatization
   	d.	adaptation

   A researcher is setting up an experiment to measure basal metabolic rate in songbirds. Which of the following would be the best set of conditions for the birds immediately before and during the measurement?

   	a.	House the birds in a cage with no food for a few hours before measurement; conduct measurements in a room the same temperature as the room where housed
   	b.	House the birds in a cage with no food for a few hours before measurement; conduct measurements in a colder room than the room where housed, and exercise the birds.
   	c.	House the birds in a cage with plenty of food and water to avoid stress; conduct measurements in a room the same temperature as the room where housed.
   	d.	House the birds in a cage with plenty of food and water to avoid stress; conduct measurements in a warmer room than the room where housed.

2. Which of the following events produces the "pull" that is associated with myosin and actin sliding past one another?

   	a.	the binding of ATP to the myosin head
   	b.	the hydrolysis of ATP
   	c.	the release of a phosphate from the myosin head after ATP is hydrolyzed
   	d.	the myosin head with an empty ATP binding site

Answer 1

QUESTION 1

Option A:- Incorrect

Reason:-Evolution refers to the gradual changes in a population over a period of time. These variations and changes in the population are the results of mutation, recombination, genetic drift, natural selection and random mating. These beneficial variations are passed down to the next generation during sexual reproduction.

Option B:-Incorrect

Reason:-Trade off in evolutionary study is the decision to lose, let go off one property in return of something else.

Option C:-Correct

Reason:-Acclimatization refers to the change and modification in the behavior, physical or metabolic process in order to withstand the seasonal changes and other temporary changes in environmental conditions. Here in the above case of Chum salmon, it adjusts itself to the changing surrounding and different concentrations of salts in sea and river by destruction and production of the specific types of cells.

Salmon produces specific cells that serve as pumps to maintain the optimal salt concentration of the body when the salmon migrate to the marine water, When they return back to freshwater for spawning they destroy these specific cells as they are of no use anymore.

Option D:-Incorrect

Reason:-Adaption is an evolutionary process that enables an organism to better suit and survive in its natural habitat.