Answer:
Mold fossil.
Explanation:
The clamshell shaped cavity is a mold fossil owing to the fact that the clamshell died, its body deteriorated but while it is deteriorating it is being covered by sediment. As a result when the clamshell completely disappears it will leave an impression on the sediment, in other words, it is a mold of the prehistoric clamshell.
Answer:
B
Explanation:
The Ames test is a bacteriological technique commonly used to determine if a particular chemical or substance can cause mutations. To achieve this, researchers use bacteria (commonly <em>Salmonella typhimurium</em>) as this bacteria strain is unable to grow in a medium that does not contain histidine (a very important amino acid in the biosynthesis of proteins). If the studied substance is able to cause mutations, bacteria will mutate, and they will be able to grow on that particular media even if they don’t have histidine for their metabolism. Therefore, if there are colonies growing, the chemical being tested is mutagenic.
I hope this clarify your inquiry.
Answer:
When oestrogen rises to a high enough level it causes a surge in LH from the pituitary which causes ovulation where an egg is released from the follicle (Day 14 of the cycle). The follicle becomes the corpus luteum and this produces oestrogen and progesterone which inhibit FSH and LH production by the pituitary.
Explanation: