Why did red spots appear on the steam or flower?

Do red spots appear on the leaves of flowers of any of the plants?

When did Homosaplens appear on the earth?

Spots appear on leaves because of

Why did this happen ?

Did you see any red spot in the stem or other parts of any of the plants?

When did early human like form appear on the earth?

Why does the sky sometimes appear white ?

Why does the setting sun appear red ?

Padma took a little sodium hydroxide in a beaker and dipped a red litmus paper into it. She observed red litmus paper turned blue. She took dilute hydrochloric acid in the same beaker and dipped a blue litmus paper into it. The blue litmus paper did not turn red. Why ?