Mammalian fertilization comprises sperm migration through the female reproductive tract, biochemical and morphological changes to sperm, and sperm-egg interaction in the oviduct. Recent gene knockout approaches in mice have revealed that many factors previously considered important for fertilization are largely dispensable, or if they are essential, they have an unexpected function. These results indicate that what has been observed in in vitro fertilization (IVF) differs significantly from what occurs during “physiological” fertilization. This Review focuses on the advantages of studying fertilization using gene-manipulated animals and highlights an emerging molecular mechanism of mammalian fertilization.
Answer:
B
Explanation:
Mass is constant. Weight varies due to gravity.
For example, On earth you weigh 75kg but on Jupiter you weigh 275kg (not accurate). Your weight has varied. However your mass is the same on both planets.
Answer: Option C
Explanation:
Color blindness is a common hereditary condition which means it usually passes from parents. Red green color blindness is passed on from the mother to the son.
The chromosome number 23 is the sex chromosome also responsible for colorblindness. As it is sex linked the son can receive the recessive allele from the mother.
The mother of the child had a recessive allele which she transferred into her son. As it is sex inherited disease the son is affected by gene carried from mother.
C. Lactic acid fermentation
