The research of astronomy during the time period of 1970 - 1990 is given below:
<u>Date</u>                                                   <u>Event</u>
1. 15 June 1974               Black Brant VC sounding rocket from White Sands.
2. 14 May 1973              Launch of Skylab, the USA's first space station
3. 26 July 1971          	Launch of Apollo 15
<h3>What is Astronomy?</h3>
This refers to the branch of science that deals with celestial bodies and their relation to each other.
Hence, from information about astronomy, between the time period 1970 - 1990 as it was on the 26th of December, 1974 that the Soviet space station Salyut-4 was launched.
The event I think had the greatest impact in astronomical history during this time period was the launch of Apollo 16.
Read more about astronomy here:
brainly.com/question/1141458
#SPJ1
 
        
             
        
        
        
Answer:
A.
Explanation:
Water was added to the reaction after the completion of the reaction so as to lower the solubility if the product in the solution therefore, the product can be precipitated out. On adding water the reaction moves in forward direction and more product is formed. (By Le Chatelier's principle). Thus, the precipitation occurs. Hence, option A is correct. 
 
        
             
        
        
        
Answer:
The correct answer is cation. See the explanation below, please.
Explanation:
An atom with a net charge, either positive or negative, is called an ion. In the event that an atom loses an electron (or more), that is, it will have more protons than electrons, and its net charge will be positive, it will be called cation. In the opposite direction, if an atom gains electrons, it will have a negative net charge, called anion.
 
        
             
        
        
        
Answer:
Explanation:
There is a formula for this:
M = DRT/P where M = molar mass. This just derived from PV = nRT where you say n = grams/molar mass. However, just with this formula, we can get D which is density at STP (1 atm and 273K). We find that D = 6.52g/L.
 
        
                    
             
        
        
        
Answer: the best statement is 1 (Vitamin B12 (cobolamin) is missing from the vegan diet and very low in the lactovegetarian diet.)
Explanation:
Vitamin B12( cobalamin) is a water soluble vitamin that is essential in the formation of red blood cells. It also serves as a coenzyme in the metabolic reaction of the body. Such reaction includes: 
- the remethylation of methionine from homocysteine which is catalyzed by methionine synthase and requires methylcobalamin.
The deficiency of vitamin B12 can lead to the following:
- elevated homocysteine , 
- an increase in methylmalonate 
This is due to deficiencies in methionine synthase and methylmalonic acid mutase, respectively in individuals on vegan diet for several years.
Vegans are vegetarians that don't include diary or animal products in their meals. This predisposes them to lack of Vitamin B12. Dairy products provide some vitamin B12 in the lactovegetarian diet. Therefore statement 1 is the correct answer, thanks.