General Science

Step 1: Understanding Marchantia.
In Marchantia, antheridiophores (male sex organs) are borne on the male thallus, not on the female thallus. Archegoniophores (female sex organs) are found on female thallus.
Step 2: Analyzing other statements.
(B) Correct — Chara is monoecious, i.e., both sex organs are present on the same thallus.
(C) Correct — Gametes are always haploid, formed after meiosis from diploid cells.
(D) Correct — Zoospores are formed in Chlamydomonas.
Step 3: Conclusion.
The incorrect statement is (A), because antheridia are not present on female thallus in \textit{Marchantia}.

Step 1: Recall base pairing in DNA.
In DNA, the nitrogenous bases follow specific pairing rules where Adenine (A) always pairs with Thymine (T), and Cytosine (C) always pairs with Guanine (G).
Step 2: Review the options.
- Option (A) G = T is incorrect because Guanine (G) pairs with Cytosine (C), not Thymine (T).
- Option (B) C = G is correct based on the base pairing rules.
- Option (C) G = C is correct, but it’s not the best answer to the question which asks for a “correct pair.”
- Option (D) A = T is the correct pairing in DNA as per the standard base pairing rules.
Step 3: Conclude.
The correct pair according to the base pairing rules is A = T, making option (D) the correct answer.
Final Answer: