Crossing over. Parts of sister chromatids will sometimes switch places with the parallel part, resulting in a completely unique DNA sequence.
After two half-lives or 60 years, 7.5 g of the element will be left.
<u>Explanation:</u>
<u>Half-life:</u>
- In simple words, Half-life can be defined as the amount of time needed for a quantity to fall to half its value as contained at the beginning of the time period.
- In this problem the half-life of the element is thirty years, then after thirty years half of the sample would have decayed and half would be left as it is.
- After thirty years (The first half-life ) 30 /2 = 15 g declines and 15 g remains disappeared.
- And after another sixty years (The two half-lives) 15 /2 = 7.5 g declines and 7.5 g remains disappeared.
- After two half-lives or 60 years, 7.5 g of the element will be left.
The correct option is C.
Lantana is a tropical evergreen shrub which is usually cultivated as ornamental flowers. It is a plant that threatening livestock especially in Australia. The signs of lantana poisoning in livestock include: excessive skin sensitivity to sunlight, liver damage, yellow coloration of the white part of the eyes, reddening of the eyes, swelling of the ears, etc.
If the poisoning case is severe, the animal death will occur between two to four days, but generally, untreated animals usually die within one to three weeks.
D because they are complete systems
