The MRI machine allowing us to see how the brain reacts to different stimuli is one.
Answer:
Testing positive for HIV means a high chance of death and a good chance of lower reproduction rates. But some people are immune to HIV, which makes them more evolutionarily fit, likely to live longer, likely to reproduce more, which would increase the frequency of the immune allele in the population. Over time, this increase in frequency of the gene that causes immunity could spread across the human race and cause it to evolve.
Answer:
Option D, Gastric Juices
Explanation:
The second line of defense is a non specific defense mechanism in which no specific individual is targeted but all invaders are killed in general way. Some common mode of second line of defense are - Phagocytic cells (white blood cells), inflammatory responses, macrophage system etc. The second line of defense comes into action when the invader has surpassed the first line of defense which include either physical barrier like skin, mucous membrane, hair, cilia etc. or chemical barriers like gastric juices, saliva, Hyaluronic acid etc.
Hence, gastric juice does not belong to second line of defense.
Thus, option D is correct.
Answer:
Explanation:
When enzyme does not work properly it is said to be inactive and this affect its efficiency.
Substrate concentration - Enzyme requires adequate substrate concentration to be effective, when the concentration is high the enzyme activity increases and when it is low it decreases.
Temperature - Enzymes are more active at specific temperature at very high temperature enzyme can be denatured leading to a loss of its activity. Hence, enzyme should be made to work at its optimum.
pH- Enzymes are active at specific pH, when the pH is altered enzymatic activity may be reduced or enzyme become inactive. Hence, pH of enzymes should be maitained.
Twins are made when to embryos split