How can you determine the past arrangement of leaves on a bare twig?

We can determine the past arrangement of leaves on a bare twig by looking at the arrangement of axillary buds and leaf scars.

Explanation:

The arrangement of leaves on a branch or stem is called phyllotaxy.Leaves are formed at stem nodes.They bear axillary bud on their axil.Axillary bud give rise to flowers and new branches.When leaves shred off we can determine their phyllotaxy by looking at the axillary buds on the nodes.When leaves fall off the stem, they leave scars at the nodes, these scars can also be considered to find out the attachment of leaves and phyllotaxy.

Common leaf arrangements are:

Alternate.- When one leaf arises at each node and successive leaves develop on alternate sides .se.g. As seen in BarberryOpposite- When two leaves arise at one node and on the opposite side of the stem. E.g as seen in maple.Whorled.- When three or more leaves arise at a node forming a whorl.

answer: carbon 14 can only be used to determine the age of the organisms that were once living, and igneous rocks are non living.

explanation:

carbon 14 dating is used to determine the age of the sample by estimating the amount of carbon 14 present in the sample and then comparing it with a reference standard.carbon 14 is a isotope of carbon which is radioactive and unstable. carbon 14 is assimilated by all plants and animals throughout their life from carbon dioxide. however, one the organisms die they stop this assimilation and the carbon 14 content starts to decrease.by knowing how much of carbon 14 is left in an organism after his death, one can estimate the age of the organism. the materials whose age can be estimated by carbon 14 method are the organic compounds. however, some inorganic compounds such as aragonite   shell can also be dated.however, if we consider the igneous rocks it is a non living component which never accumulated carbon 14 in it and thus, we cannot use carbon 14 dating method to estimate its age.