Catastrophism is the theory that the Earth has largely been shaped by sudden, short-lived, violent events, possibly worldwide in scope.[1] This is in contrast to uniformitarianism (sometimes described as gradualism), in which slow incremental changes, such as erosion, created all the Earth's geological features. The proponents of uniformitarianism held that the present was the key to the past, and that all geological processes (such as erosion) throughout the past were like those that can be observed now. Since the early disputes, a more inclusive and integrated view of geologic events has developed, in which the scientific consensus accepts that there were some catastrophic events in the geologic past, but these were explicable as extreme examples of natural processes which can occur.
Cyclins
are the chemicals that regulate the cell cycle. Cyclins work by regulating the timing
of the cell cycle in eukaryotic cell. Cyclins activates cyclin dependent
kinases (CDKs) (an enzyme that works by adding <span>negatively charged phosphate groups to other
molecules in a process called phosphorylation) by binding to it to form a cyclin-Cdk
complex. This complex then functions by acting as a signal to the cell to move
to the next cell cycle phase. At the end of the event, the cyclin is degraded, Cdk
is deactivated, therefore signaling exit from a specific phase.</span>
Answer:
The trait is Y-linked
Explanation:
The only plausible explanation behind the inheritance pattern shown by the porcupine trait is that it is <u>Y-linked</u>.
<em><u>Y-linked traits are limited to the Y chromosome only</u></em><em>, a sex chromosome that is peculiar to only the male gender. Chromosomally, females are XX while males are XY. Hence, only the male gender has the genetic capacity to inherit the porcupine trait. This is why only the sons of Edward Lambert, and never the daughters, exhibited the trait. </em>
Answer:
True
Explanation:
Oogenesis includes the formation of one egg cell from a single oocyte or egg mother cell. The diploid primary oocytes in the ovaries enter into the first meiotic division and form a haploid secondary oocyte and a haploid first polar body. After fertilization, the secondary oocytes complete the meiosis-II and forms one large ovum and a second polar body. The ovum formed by meiosis-II is much larger than the second polar body due to the unequal distribution of cytoplasm during meiosis-II. This imparts enough amount of cytoplasm in the zygote to support the mitosis without any cell growth.
