Answer: Layer a is 500 million years old.
Explanation:
Trilobite is a member of the group of extinct arthropods found as fossils and they can be identified by the three-lobed as well as three segmented forms. These were the marine animals. These were appeared initially in the Cambrian Period. They used to live 542 million years ago so the fossils can be estimated to be aged of 500 above years old. These animals used to dominate in the sea area.
Answer:
c
Explanation:
it weakens an ecosystem.biodiversity is the slight changes of one organisim to the next inside a species. when a species looses biodiversity, the traits that the one organisim had are gone and none of the others can adapt this trait. adaptation is what keeps speicies alive. thus, loss of biodiversity is bad and weakens an ecosystem.
Answer:
B. Burns cleaner than coal
B, Provide nutritional support to the embryo. It is not D, as the breasts are not part of the female reproductive system. It isn't C because during pregnancy, fetal and maternal blood do not mix. It also isn't D since women do not produce sperm.
