b. anthrax
c. vaccines
d. all of the above
Answer:
its c : When blood sugar concentration is above normal, the endocrine system releases hormones that lower the blood sugar concentration until it reaches a normal level, and the release of the hormones slows.
Explanation:
A) Positive feedback loop
B) Positive feedback loop
C) Negative feeback loop
B. Mesosaursus, an ancient reptile, had been discovered in South America and Africa.
C. Glacial deposits and rock surfaces scoured and polished by glaciers are found in South America, India, Africa, and Australia.
D. One type of rock found in Brazil matched a rock found in western Africa