Answer:
Specialized cells are the cells though they are similar, but cells differ in size, shape and depending upon their function in body.
Example of specialized cells are: Blood cells, Nerve cells, Reproductive cells.
Tissues are made up of specialized cells, those tissues make up organs, organs make up system and systems make up bodies.
Algae and nitrogen-fixing bacteria are photosynthetic organisms.
Answer:
Because older cultures of gram-positive bacteria tend to lose their ability to retain crystal-violet in the peptidoglycan of their cell walls and can be confused with gram-negative bacteria.
Explanation:
Gram staining is used to differentiate between two major groups of bacteria. Gram-positive and gram-negative, these bacteria differ in the amount of peptidoglycan in their cell walls. Gram-positive bacteria have a higher amount of peptidoglycan, which absorbs the violet crystal complex used in gram staining, staining them purple/violet. Old cultures of gram-positive bacteria tend to lose the ability to retain the violet crystal and are stained by safranine, staining them red/pink and appear to be gram-negative.
All are aspects of antibiotics resistance in bacteria.
• overuse of antibiotics in humans
• bacteria can reproduce so quickly
• any use of antibiotics will select for resistant bacteria
• overuse of antibiotics in livestock
Answer:
Option D, A subject is observed both before and after two exposures to the treatment.
Explanation:
In A-B-A-B design the alphabets have following meaning
a) First A – It is the baseline value or the value measured before treatment
b) First B – It is the treatment measurement
c) Second A - It is the withdrawal of treatment
d) Second B – It is the reintroduction of treatment
The second A is known as the reversal phase in which the intervention is withdrawn to see if the target behavior returns to the baseline behaviour
Thus , there are two measurements involved one before the intervention and second after the intervention
Option D is correct
