Answer:
D.) both a and c
Explanation:
Past observations made early in history as well as telescopes and space probes are very important in studying our universe and galaxies. 
- Space probes are increasingly gaining momentum as technological and scientific advancements are being made. 
- Telescopes are used to see or picture objects that are very far away in space. 
- Also, understanding the past records and historical data is essential for the study of the universe. 
Microscopes are not used in galactic studies. They are only used to study the world of micro-organisms. 
 
        
             
        
        
        
A change in the morphology of the leaves generated can frequently be used to detect when an apical meristem transition from the juvenile to the mature vegetative phase.
<h3><u>Apical meristem: What is it?</u></h3>
The growth zone within the tips of new shoots and leaves as well as the root tips of plants is known as the apical meristem. One of three meristem types, or tissues that can differentiate into distinct cell types, is the apical meristem. Plant growth takes place in the meristem tissue. 
Apical growth is defined as taking place at the top and bottom of the plant. While lateral meristems are found between branches, intercalary meristems grow in girth like those of woody plants. The apical meristem is essential for expanding both the roots' and leaves' access to light energy and nutrients. For plants to succeed, they need to grow in both of these directions.
Learn more about apical meristem with the help of the given link:
brainly.com/question/798517
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Answer:
Plants and other creatures utilize photosynthesis to convert light energy into chemical energy, which is then released to power the organism's metabolic processes through cellular respiration.
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