Answer: Leaves in a cactus are modified into spines to reduce loss of water from leaves by transpiration. Then the plant makes from the process of photosynthesis which is performed by the stem.
Explanation:
B. Glucose and O2
The products are H2O and CO2
Cells are combined in a structure called tissue wich have the same properties like the cells wich are formed by.
The answer to your question is called terminal velocity.
In eukaryotic cells the DNA can be found in the nucleus mainly. so DNA replication takes place in the nucleus during the S phase of the cell cycle.
Also in eukaryotic cells there are mitochondria and chloroplasts (plants) and these have circular DNA and they also get replicated (according to their own mechanism).
Prokaryotic cells don't contain a nucleus. They do not contain DNA in the cytoplasm and thus the DNA replication will take place here.
I really hope this helps!