The answer is hard tissue.
Usually, hard tissue, such as bones and teeth or exoskeleton is much more preserved than soft tissue (organs, skin, etc.). Fossils become fossils by a process of mineralization. Hard tissues are more mineralized during life than organs. So it is no surprise that hard tissues take part in the process of mineralization and is preserved in fossils, unlike soft tissues.
        
             
        
        
        
Hmm good question. Well I would have to test it for where there are no living life. I would have to build another NASA in the County because there is plenty of room there. Mars is made out of Dusty Crust that is about 30 miles thick. And let's say that the desert's Dusty Crust is about 5 miles - 15 miles thick. That will give about the same amount of surface that mars has. So we would know what to build for a perfect lander to work on Mars. This isn't much but it is something.
        
             
        
        
        
Answer:
glucagon 
Explanation:
Glucagon is a hormone that is involved in controlling blood sugar (glucose) levels. It is produced by the alpha cells, found in the islets of Langerhans, in the pancreas, from where it is released into the bloodstream.
 
        
             
        
        
        
Answer:
El híbrido va a ser esteril.
Explanation:
En la cruza entre dos especies distintas, cuando ocurre, existen distintos mecanismos de aislamiento reproductivo, que son barreras que inhiben o interrumpen el flujo génico entre especies distintas. Es decir que no habrá exito reproductivo de estas cruzas. Se trata de caracteres biológicos propios de cada especie que previenen la reproducción con otras especies.
Estos mecanismos de aislamiento reproductivo pueden ser precigóticos o postcigóticos.  
   1.Pre-copulatorios o pre-cigóticos:
- Ecológico o por aislamiento de hábitat;
- Por incompatibilidad de gametas.  
   2. Post-copulatorios o cigóticos:
- Inviabilidad del híbrido;
- Híbrido con viabilidad o fertilidad disminuido;
- Interacciones citoplasmáticas.
La mula es producto de la cruza entre dos especies distintas: una yegua (Equus ferus caballus) y un burro (Equus africanus asinus). Es un ejemplo de la accion de mecanismo poscigótico, en el cual se forma un híbrido viable esteril. Este ejemplar puede nacer, crecer y sobrevivir, pero que no puede producir gametas funcionales, por lo cual no puede reproducirse.  
 
        
             
        
        
        
The answer to your question is Letter C   <-- ANSWER 
Steroid is a molecule made up of four carbon rings with other atoms bonded to those rings. 
Hope this Helps