I think t or r............
Ribosomes, mitochondria, ER and chloroplast.
Answer:
D) homologous pairs of chromosomes form tetrads
Explanation:
During prophase I, the homologous chromosomes condense and become visible as the x shape we know, pair up to form a tetrad, and exchange genetic material by crossing over.
Correct answer is (D. Once created in bone marrow, they circulate for our lifetime)