More Harmful Effects of Smoking Weed While Breastfeeding. More medical studies need to be done to determine marijuanaâs effects on breast milk, but below are some of the areas studies have indicated contain risk factors.urthermore, marijuana use can diminish the abilities of a mother to take care of her newborn. The American Academy of Pediatrics advises nursing mothers not to use marijuana while breastfeeding. However, in some states medical marijuana is used to treat anxiety and other medical conditions.
We can see fossils of many other reptiles in rock of the same age and even older, but Archaeopteryx lithographica is the oldest known fossil to have feathers. We conclude that this animal is a link between reptiles and birds and that birds are descended from reptiles.ossils can be used to recognize rocks of the same or different ages. The fossils in this figure are the remains of microscopic algae. The pictures shown were made with a scanning electron microscope and have been magnified about 250 times.
Fossil of shell. Fossils are very common in sedimentary rocks, such as limestone, but rare in metamorphic rocks, such as marble. Fossils are never found in igneous rocks, such as granite. Sediment layers settle over the dead animals and plants that then turn into fossils.ther sediments form from the skeletons of animals, and from plants and other living things. Eventually, these sediments get buried and are squashed together to form sedimentary rocks. Sedimentary rocks make up around 75 per cent of the rocks on the Earthâs surface. 1  Rock cycle.