Hey pizzalover! The answer from this question would be
a. oxygen
Hope it helps
 
        
                    
             
        
        
        
Photosynthesis produces oxygen and water. Photosynthesis is the result of a cycle. Humans use oxygen for respiration, the product produced from human respiration is carbon dioxide. Then plants absorb carbon dioxide from the air and turn it into oxygen with photosynthesis, this goes on and on as a cycle.
        
             
        
        
        
Vascular plants have a vascular system while nonvascular plants have NO vascular system.
Explanation:
The vascular system is made of phloem – that transports food- and xylem- that transports water and minerals- in the higher plants. Examples of these higher plants are like trees and shrubs. These plants can take up water and nutrients from the soil and transport them up the plants to the leaves. 
Lower plants have no vascular system (avascular). They mainly absorb food and water readily from their environment even through their leaves. This is why these plants are mainly found in humid areas like waterways, like canals. Examples of such lower plats are ferns and mosses. 
 
        
             
        
        
        
Answer:
For a full list of topics: A-Z Index ... We know that not all birth defects can be prevented. ... avoid harmful substances, choose a healthy lifestyle, and talk with your ... one month before and during pregnancy, it can help prevent major birth defects of ... planning a pregnancy, she should not stop taking medications she needs or .
Explanation: