Answer:eukaryotes can be single celled
Explanation:
After the fossils are buried in the mud the soft tissues start to decompose rapidly. Leaving only the hard shells or bones of the animal. With time, sediment starts to build up on the top and then hardens into rock. The bones then start to decay, minerals start to enter and then end up replacing the organic material cell by cell in a process that is known as "petrification." So the answer you are looking for is B, Mud can prevent oxygen from reaching the dead organism.
The number one determining factor in the types of organisms that can live in a body of water is salinity, the amount of salt in a body of water. Hope this helped!
<span>The correct option is this: THE HEART BEGINS BEATING.
A fertilized egg takes about 40 weeks to reach full maturity. At week 5, the developing fetus resemble a tadpole; at this stage, the circulatory system has begin to form and the tiny heart has started beating and the baby is the size of a sesame seed. By week 6, the heart beat of the baby can fully be detected through scan.</span>
