Please help i am giving away brainilest 1. A main function of the leaf petiole is

A. none of these

B. to keep the leaf away from the secondary meristem of the stem.

C. to produce pollen.

D. to extend the leaf blade away from the stem so the blade can collect sufficient sunlight.

no dam links

When analyzing tree rings, what do scientists assume a thin ring indicates?

In order to study genetic mutations, scientists must study genetic material. which statement describes the genetic material scientists are most likely studying? a) they study alleles that contain chromosomes, which are rna.b) they study alleles that contain genes, which are chromosomes.c) they study chromosomes that contain genes, which are dna segments.

Substances that can pass through cell membranes by diffusion include a. na ions. b. proteins c. glucose. d. oxygen.